Computer System Including CPU or Peripheral Bridge to Communicate Serial Bits of Peripheral Component Interconnect Bus Transaction and Low Voltage Differential Signal Channel to Convey the Serial Bits

ABSTRACT

A computer system for multi-processing purposes. The computer system has a console comprising a first coupling site and a second coupling site. Each coupling site comprises a connector. The console is an enclosure that is capable of housing each coupling site. The system also has a plurality of computer modules, where each of the computer modules is coupled to a connector. Each of the computer modules has a processing unit, a main memory coupled to the processing unit, a graphics controller coupled to the processing unit, and a mass storage device coupled to the processing unit. Each of the computer modules is substantially similar in design to each other to provide independent processing of each of the computer modules in the computer system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/744,287 filed Jan. 17, 2013, which is a continuation of U.S. patentapplication Ser. No. 13/649,084, filed Oct. 10, 2012, which is acontinuation of U.S. patent application Ser. No. 13/560,924, filed Jul.27, 2012 (Now U.S. Pat. No. 8,626,977), which is a continuation of U.S.patent application Ser. No. 13/087,912, filed Apr. 15, 2011 (Now U.S.Pat. No. 8,234,436), which is a continuation of U.S. patent applicationSer. No. 12/504,534, filed Jul. 16, 2009 (Now U.S. Pat. No. 8,041,873),which is a continuation of U.S. patent application Ser. No. 12/077,503,filed Mar. 18, 2008 (Now U.S. Pat. No. 7,676,624), which is acontinuation of U.S. patent application Ser. No. 11/166,656, filed Jun.24, 2005 (Now U.S. Pat. No. 7,376,779), which is a continuation of U.S.patent application Ser. No. 11/097,694, filed Mar. 31, 2005 (Now U.S.Pat. No. 7,363,415), which is a continuation of U.S. patent applicationSer. No. 10/772,214, filed Feb. 3, 2004 (Now U.S. Pat. No. 7,099,981),which is a continuation of U.S. patent application Ser. No. 09/569,758,filed May 12, 2000 (Now U.S. Pat. No. 6,718,415), and which claimedpriority to U.S. Provisional Patent Application No. 60/134,122, filedMay 14, 1999. These applications are hereby incorporated by reference intheir entirety.

BACKGROUND OF THE INVENTION

The present invention relates to computing devices. More particularly,the present invention provides a system including a plurality ofcomputer modules that can independently operate to provide backupcapability, dual processing, and the like. Merely by way of example, thepresent invention is applied to a modular computing environment for desktop computers, but it will be recognized that the invention has a muchwider range of applicability. It can be applied to a server as well asother portable or modular computing applications.

Many desktop or personal computers, which are commonly termed PCs, havebeen around and used for over ten years. The PCs often come withstate-of-art microprocessors such as the Intel Pentium™ microprocessorchips. They also include a hard or fixed disk drive such as memory inthe giga-bit range. Additionally, the PCs often include a random accessmemory integrated circuit device such as a dynamic random access memorydevice, which is commonly termed DRAM. The DRAM devices now provide upto millions of memory cells (i.e., mega-bit) on a single slice ofsilicon. PCs also include a high resolution display such as cathode raytubes or CRTs. In most cases, the CRTs are at least 15 inches or 17inches or 20 inches in diameter. High resolution flat panel displays arealso used with PCs.

Many external or peripheral devices can be used with the PCs. Amongothers, these peripheral devices include mass storage devices such as aZip™ Drive product sold by Iomega Corporation of Utah. Other storagedevices include external hard drives, tape drives, and others.Additional devices include communication devices such as a modem, whichcan be used to link the PC to a wide area network of computers such asthe Internet. Furthermore, the PC can include output devices such as aprinter and other output means. Moreover, the PC can include specialaudio output devices such as speakers the like.

PCs also have easy to use keyboards, mouse input devices, and the like.The keyboard is generally configured similar to a typewriter format. Thekeyboard also has the length and width for easily inputting informationby way of keys to the computer. The mouse also has a sufficient size andshape to easily move a curser on the display from one location toanother location.

Other types of computing devices include portable computing devices suchas “laptop” computers and the like. Although somewhat successful, laptopcomputers have many limitations. These computing devices have poordisplay technology. In fact, these devices often have a smaller flatpanel display that has poor viewing characteristics. Additionally, thesedevices also have poor input devices such as smaller keyboards and thelike. Furthermore, these devices have limited common platforms totransfer information to and from these devices and other devices such asPCs.

Up to now, there has been little common ground between these platformsincluding the PCs and laptops in terms of upgrading, ease-of-use, cost,performance, and the like. Many differences between these platforms,probably somewhat intentional, have benefited computer manufacturers atthe cost of consumers. A drawback to having two separate computers isthat the user must often purchase both the desktop and laptop to have“total” computing power, where the desktop serves as a “regular”computer and the laptop serves as a “portable” computer. Purchasing bothcomputers is often costly and runs “thousands” of dollars. The user alsowastes a significant amount of time transferring software and databetween the two types of computers. For example, the user must oftencouple the portable computer to a local area network (i.e., LAN), to aserial port with a modem, and then manually transfer over files and databetween the desktop and the portable computer. Alternatively, the useroften must use floppy disks to “zip” up files and programs that exceedthe storage capacity of conventional floppy disks, and transfer thefloppy disk data manually.

Another drawback with the current model of separate portable and desktopcomputer is that the user has to spend money to buy components andperipherals which are duplicated in at least one of these computers. Forexample, both the desktop and portable computers typically include harddisk drives, floppy drives, CD-ROMs, computer memory, host processors,graphics accelerators, and the like. Because program software andsupporting programs generally must be installed upon both hard drives inorder for the user to operate programs on the road and in the office,hard disk space is often wasted.

One approach to reduce some of these drawbacks has been the use of adocking station with a portable computer. Here, the user has theportable computer for “on the road” use and a docking station thathouses the portable computer for office use.

Similar to separate desktop and portable computers, there is nocommonality between two desktop computers. To date, most personalcomputers are constructed with a single motherboard that providesconnection for CPU and other components in the computer. Dual CPUsystems have been available through Intel's slot 1 architecture. Forexample, two Pentium II cartridges can be plugged into two “slot 1” cardslots on a motherboard to form a Dual-processor system. The two CPU'sshare a common host bus that connects to the rest of the system, e.g.main memory, hard disk drive, graphics subsystem, and others. Dual CPUsystems have the advantage of increased CPU performance for the wholesystem. Adding a CPU cartridge requires no change in operating systemsand application software. However, dual CPU systems may suffer limitedperformance improvement if memory or disk drive bandwidth becomes thelimiting factor. Also, dual CPU systems have to time-share theprocessing unit in running multiple applications. CPU performanceimprovement efficiency also depends on software coding structure. DualCPU systems provide no hardware redundancy to help fault tolerance. Inrunning multiple applications, memory and disk drive data throughputwill become the limiting factor in improving performance withmulti-processor systems.

The present invention generally relates to computer interfaces. Morespecifically, the present invention relates to an interface channel thatinterfaces two computer interface buses that operate under protocolsthat are different from that used by the interface channel.

Interfaces coupling two independent computer buses are well known in theart. A block diagram of a computer system utilizing such a prior artinterface is shown in FIG. 5. In FIG. 5, a primary peripheral componentinterconnect (PCI) bus 505 of a notebook PC 500 is coupled to asecondary PCI bus 555 in a docking system 550 (also referred to asdocking station 550) through high pin count connectors 501 and 502,which are normally mating connectors. The high pin count connectors 501and 502 contain a sufficiently large number of pins so as to carry PCIbus signals between the two PCI buses without any translation. The mainpurpose for interfacing the two independent PCI buses is to allowtransactions to occur between a master on one PCI bus and a target onthe other PCI bus. The interface between these two independent PCI busesadditionally includes an optional PCI to PCI bridge 560, located in thedocking station 550, to expand the add on capability in docking station550. The bridge 560 creates a new bus number for devices behind thebridge 560 so that they are not on the same bus number as other devicesin the system thus increasing the add on capability in the dockingstation 550.

An interface such as that shown in FIG. 5 provides an adequate interfacebetween the primary and secondary PCI buses. However, the interface islimited in a number of ways. The interface transfers signals between theprimary and secondary PCI buses using the protocols of a PCI bus.Consequently, the interface is subject to the limitations under whichPCI buses operate. One such limitation is the fact that PCI buses arenot cable friendly. The cable friendliness of the interface was not amajor concern in the prior art. However, in the context of the computersystem of the present invention, which is described in the presentinventor's (William W. Y. Chu's) application for “Personal ComputerPeripheral Console With Attached Computer Module” filed concurrentlywith the present application on Sep. 8, 1998 and incorporated herein byreference, a cable friendly interface is desired for interfacing anattached computer module (ACM) and a peripheral console of the presentinvention. Furthermore, as a result of operating by PCI protocols, theprior art interface includes a very large number of signal channels witha corresponding large number of conductive lines (and a similarly largenumber of pins in the connectors of the interface) that are commensuratein number with the number of signal lines in the PCI buses which itinterfaces. One disadvantage of an interface having a relatively largenumber of conductive lines and pins is that it costs more than one thatuses a fewer number of conductive lines and pins. Additionally, aninterface having a large number of conductive lines is bulkier and morecumbersome to handle. Finally, a relatively large number of signalchannels in the interface renders the option of using differentialvoltage signals less viable because a differential voltage signal methodwould require duplicating a large number of signal lines. It isdesirable to use a low voltage differential signal (LVDS) channel in thecomputer system of the present invention because an LVDS channel is morecable friendly, faster, consumes less power, and generates less noise,including electromagnetic interferences (EMI), than a PCI channel. Theterm LVDS is herein used to generically refer to low voltagedifferential signals and is not intended to be limited to any particulartype of LVDS technology.

Thus, what is needed are computer systems that can have multiplecomputer modules. Each computer module has dedicated memory and diskdrive, and can operate independently.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, a technique including a method anddevice for multi-module computing is provided. In an exemplaryembodiment, the present invention provides a system including aplurality of computer modules that can independently operate to providebackup capability, dual processing, and the like.

In a specific embodiment, the present invention provides a computersystem for multi-processing purposes. The computer system has a consolecomprising a first coupling site and a second coupling site, e.g.,computer module bay. Each coupling site comprises a connector. Theconsole is an enclosure that is capable of housing each coupling site.The system also has a plurality of computer modules, where each of thecomputer modules is coupled to one of the connectors. Each of thecomputer modules has a processing unit, a main memory coupled to theprocessing unit, a graphics controller coupled to the processing unit,and a mass storage device coupled to the processing unit. Each of thecomputer modules is substantially similar in design to each other toprovide independent processing of each of the computer modules in thecomputer system.

In an alternative specific embodiment, the present invention provides amulti-processing computer system. The system has a console comprising afirst coupling site and a second coupling site. Each coupling sitecomprises a connector. The console is an enclosure that is capable ofhousing each coupling site. The system also has a plurality of computermodules, where each of the computer modules is coupled to one of theconnectors. Each of the computer modules has a processing unit, a mainmemory coupled to the processing unit, a graphics controller coupled tothe processing unit, a mass storage device coupled to the processingunit, and a video output coupled to the processing unit. Each of thecomputer modules is substantially similar in design to each other toprovide independent processing of each of the computer modules in thecomputer system. A video switch circuit is coupled to each of thecomputer modules through the video output. The video switch isconfigured to switch a video signal from any one of the computer modulesto a display.

Numerous benefits are achieved using the present invention overpreviously existing techniques. In one embodiment, the inventionprovides improved processing and maintenance features. The invention canalso provide increased CPU performance for the whole system. Theinvention also can be implemented without changes in operating systemand application software. The present invention is also implementedusing conventional technologies that can be provided in the presentcomputer system in an easy and efficient manner.

In another embodiment, the invention provides at least two users toshare the same modular desktop system. Each user operates on a differentcomputer module. The other peripheral devices, i.e. CDROM, printer, DSLconnection, etc. can be shared. This provides lower system cost, lessdesktop space and more efficiency. Depending upon the embodiment, one ormore of these benefits can be available. These and other advantages orbenefits are described throughout the present specification and aredescribed more particularly below.

In still further embodiments, the present invention provides methods ofusing multiple computer modules.

The present invention encompasses an apparatus for bridging a firstcomputer interface bus and a second computer interface bus. where eachof the first and second computer interface buses have a number ofparallel multiplexed address/data bus lines and operate at a clock speedin a predetermined clock speed range having a minimum clock speed and amaximum clock speed. The apparatus comprises an interface channel havinga clock line and a plurality of bit lines for transmitting bits; a firstinterface controller coupled to the first computer interface bus and tothe interface channel to encode first control signals from the firstcomputer interface bus into first control bits to be transmitted on theinterface channel and to decode second control bits received from theinterface channel into second control signals to be transmitted to thefirst computer interface bus; and a second interface controller coupledto the interface channel and the second computer interface bus to decodethe first control bits from the interface channel into third controlsignals to be transmitted on the second computer interface bus and toencode fourth control signals from the second computer interface businto the second control bits to be transmitted on the interface channel.

In one embodiment, the first and second interface controllers comprise ahost interface controller (HIC) and a peripheral interface controller(PIC), respectively, the first and second computer interface busescomprise a primary PCI and a secondary PCI bus, respectively, and theinterface channel comprises an LVDS channel.

The present invention overcomes the aforementioned disadvantages of theprior art by interfacing two PCI or PCI-like buses using a non-PCI ornon-PCI-like channel. In the present invention, PCI control signals areencoded into control bits and the control bits, rather than the controlsignals that they represent, are transmitted on the interface channel.At the receiving end, the control bits representing control signals aredecoded back into PCI control signals prior to being transmitted to theintended PCI bus.

The fact that control bits rather than control signals are transmittedon the interface channel allows using a smaller number of signalchannels and a correspondingly small number of conductive lines in theinterface channel than would otherwise be possible. This is because thecontrol bits can be more easily multiplexed at one end of the interfacechannel and recovered at the other end than control signals. Thisrelatively small number of signal channels used in the interface channelallows using LVDS channels for the interface. As mentioned above, anLVDS channel is more cable friendly, faster, consumes less power, andgenerates less noise than a PCI bus channel, which is used in the priorart to interface two PCI buses. Therefore, the present inventionadvantageously uses an LVDS channel for the hereto unused purpose ofinterfacing PCI or PCI-like buses. The relatively smaller number ofsignal channels in the interface also allows using connectors havingsmaller pins counts. As mentioned above an interface having a smallernumber of signal channels and, therefore, a smaller number of conductivelines is less bulky and less expensive than one having a larger numberof signal channels. Similarly, connectors having a smaller number ofpins are also less expensive and less bulky than connectors having alarger number of pins.

In one embodiment, the present invention encompasses an apparatus forbridging a first computer interface bus and a second computer interfacebus, in a microprocessor based computer system where each of the firstand second computer interface buses have a number of parallelmultiplexed address/data bus lines and operate at a clock speed in apredetermined clock speed range having a minimum clock speed and amaximum clock speed. The apparatus comprises an interface channel havinga clock channel and a plurality of bit channels for transmitting bits; afirst interface controller coupled to the first computer interface busand to the interface channel to encode first control signals from thefirst computer interface bus into first control bits to be transmittedon the interface channel and to decode second control bits received fromthe interface channel into second control signals to be transmitted tothe first computer interface bus; and a second interface controllercoupled to the interface channel and the second computer interface busto decode the first control bits from the interface channel into thirdcontrol signals to be transmitted on the second computer interface busand to encode fourth control signals from the second computer interfacebus into the second control bits to be transmitted on the interfacechannel.

In one embodiment, the first and second interface controllers comprise ahost interface controller (HIC) and a peripheral interface controller(PIC), respectively, the first and second computer interface busescomprise a primary PCI and a secondary PCI bus, respectively, and theinterface channel comprises an LVDS channel.

In a preferred embodiment, the interface channel has a plurality ofserial bit channels numbering fewer than the number of parallel buslines in each of the PCI buses and operates at a clock speed higher thanthe clock speed at which any of the bus lines operates. Morespecifically, the interface channel includes two sets of unidirectionalserial bit channels which transmit data in opposite directions such thatone set of bit channels transmits serial bits from the HIC to the PICwhile the other set transmits serial bits from the PIC to the HIC. Foreach cycle of the PCI clock, each bit channel of the interface channeltransmits a packet of serial bits.

The HIC and PIC each include a bus controller to interface with thefirst and second computer interface buses, respectively, and to managetransactions that occur therewith. The HIC and PIC also include atranslator coupled to the bus controller to encode control signals fromthe first and second computer interface buses, respectively, intocontrol bits and to decode control bits from the interface channel intocontrol signals. Additionally, the HIC and PIC each include atransmitter and a receiver coupled to the translator. The transmitterconverts parallel bits into serial bits and transmits the serial bits tothe interface channel. The receiver receives serial bits from theinterface channel and converts them into parallel bits.

According to the present invention, a technique including a method anddevice for securing a computer module using a password in a computersystem is provided. In an exemplary embodiment, the present inventionprovides a security system for an attached computer module (“ACM”). Inan embodiment, the ACM inserts into a Computer Module Bay (CMB) within aperipheral console to form a functional computer.

In a specific embodiment, the present invention provides a computermodule. The computer module has an enclosure that is insertable into aconsole. The module also has a central processing unit (i.e., integratedcircuit chip) in the enclosure. The module has a hard disk drive in theenclosure, where the hard disk drive is coupled to the centralprocessing unit. The module further has a programmable memory device inthe enclosure, where the programmable memory device can be configurableto store a password for preventing a possibility of unauthorized use ofthe hard disk drive and/or other module elements. The stored passwordcan be any suitable key strokes that a user can change from time totime. In a further embodiment, the present invention provides apermanent password or user identification code stored in flash memory,which also can be in the processing unit, or other integrated circuitelement. The permanent password or user identification code is designedto provide a permanent “finger print” on the attached computer module.

In a specific embodiment, the present invention provides a variety ofmethods. In one embodiment, the present invention provides a method foroperating a computer system such as a modular computer system andothers. The method includes inserting an attached computer module(“ACM”) into a bay of a modular computer system. The ACM has amicroprocessor unit (e.g., microcontroller, microprocessor) coupled to amass memory storage device (e.g., hard disk). The method also includesapplying power to the computer system and the ACM to execute a securityprogram, which is stored in the mass memory storage device. The methodalso includes prompting for a user password from a user on a display(e.g., fiat panel, CRT). In a further embodiment, the present methodincludes a step of reading a permanent password or user identificationcode stored in flash memory, or other integrated circuit element. Thepermanent password or user identification code provides a permanentfinger print on the attached computer module. The present inventionincludes a variety of these methods that can be implemented in computercodes, for example, as well as hardware.

Numerous benefits are achieved using the present invention overpreviously existing techniques. The present invention providesmechanical and electrical security systems to prevent theft orunauthorized use of the computer system in a specific embodiment.Additionally, the present invention substantially prevents accidentalremoval of the ACM from the console. In some embodiments, the presentinvention prevents illegal or unauthorized use during transit. Thepresent invention is also implemented using conventional technologiesthat can be provided in the present computer system in an easy andefficient manner. Depending upon the embodiment, one or more of thesebenefits can be available. These and other advantages or benefits aredescribed throughout the present specification and are described moreparticularly below.

These and other embodiments of the present invention, as well as itsadvantages and features, are described in more detail in conjunctionwith the text below and attached Figs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of a computer system according to anembodiment of the present invention;

FIG. 2 is a simplified block diagram of a computer system according toan alternative embodiment of the present invention;

FIG. 3 is a simplified block diagram of a compeer system according to afurther alternative embodiment of the present invention, and

FIG. 4 is a simplified flow diagram of a method according to anembodiment of the present invention.

FIG. 5 is a block diagram of a computer system using a prior artinterface between a primary and a secondary PCI bus.

FIG. 6 is a block diagram of one embodiment of a computer system usingthe interface of the present invention.

FIG. 7 is a partial block diagram of a computer system using theinterface of the present invention as a bridge between the north andsouth bridges of the computer system.

FIG. 8 is a partial block diagram of a computer system in which thenorth and south bridges are integrated with the host and peripheralinterface controllers, respectively.

FIG. 8A shows an attached computer module with IntegratedCPU/NB/Graphics and Integrated HIC/SB.

FIG. 8B shows an attached computer module with single chip fullyintegrated: CPU, Cache, Core Logic, Graphics controller and Interfacecontroller.

In an implementation with South Bridge in Peripheral Console, FIG. 8Cshows an example of an attached computer module with IntegratedCPU/North Bridge/Graphics and Peripheral Console with IntegratedPeripheral Interface Controller and South Bridge.

FIG. 9 is a block diagram of one embodiment of the host interfacecontroller and the peripheral interface controller of the presentinvention.

FIG. 10 is a detailed block diagram of one embodiment of the hostinterface controller of the present invention.

FIG. 11 is a detailed block diagram of one embodiment of the PIC of thepresent invention.

FIG. 12 is a table showing the symbols, signals, data rate anddescription of signals in a first embodiment of the XPBus.

FIG. 13 is a table showing the information transmitted on the XPBusduring two clock cycles of the XPBus in one embodiment of the presentinvention where 10 data bits transmitted in each clock cycle of theXPBus.

FIG. 14 is a table showing information transmitted on the XPBus duringfour clock cycles of the XPBus in another embodiment of the presentinvention where 10 data bits are transmitted in each clock cycle of theXPBus.

FIG. 15 is a schematic diagram of the signal lines PCK, PD0 to PD3, andPCN.

FIG. 16 is a table showing the names, types, number of pins dedicatedto, and the description of the primary bus PCI signals.

FIG. 17 is a block diagram of one embodiment of a computer systememploying the present invention.

FIG. 18 is a block diagram of an attached computing module (ACM).

FIG. 19 illustrates an external view of one embodiment of an ACM.

FIG. 19B illustrates one possible embodiment of a computer bay.

FIG. 20 illustrates the internal component layout for one embodiment ofan ACM.

FIG. 21 is a block diagram of a peripheral console (PCON).

FIG. 22 is a simplified layout diagram of a security system for acomputer system according to an embodiment of the present invention;

FIG. 23 is a simplified block diagram of a security system for acomputer module according to an embodiment of the present invention;

FIG. 24 shows an attached computer module with a “Plug & Display” portand direct power connection;

FIGS. 25 and 26 are tables including the pin number, symbol, signal,standard and description for the pins on the peripheral and videoconnectors, respectively.

FIG. 27 is a table showing different types of first nibbles and theircorresponding data packet types.

FIG. 28 is a block diagram of another embodiment of the HIC and PIC ofthe present invention and the interface therebetween.

FIG. 29 is a detailed block diagram of another embodiment of the HIC ofthe present invention.

FIG. 30 is a detailed block diagram of another embodiment of the PIC ofthe present invention.

FIG. 31 is a table showing the symbols, signals, data rate anddescription of signals transmitted in a second embodiment of the XPBus.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, a technique including a method anddevice for multi-module computing is provided. In an exemplaryembodiment, the present invention provides a system including aplurality of computer modules that can independently operate to providebackup capability, dual processing, and the like.

FIG. 1 is a simplified diagram of a computer system 100 according to anembodiment of the present invention. This diagram is merely anillustration and should not limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. The computer system 100 includes anattached computer module (i.e., ACM) 113, a desktop console 101, amongother elements. The computer system also has another ACM module 117.Each ACM module has a respective slot 121, 119, which mechanicallyhouses and electrically couples each ACM to the computer console. Alsoshown is a display 111, which connects to the console. Additionally,keyboard 109 and mouse 115 are also shown. A second display 102,keyboard 105, and mouse 107 can be coupled to the console in someoptional embodiments to allow more than one user to operate the computersystem. The computer system is modular and has a variety of componentsthat are removable. Some of these components (or modules) can be used indifferent computers, workstations, computerized television sets, andportable or laptop units.

In the present embodiment, each ACM 113 includes computer components aswill be described below, including a central processing unit (“CPU”).IDE controller, hard disk drive, computer memory, and the like. Thecomputer module bay (i.e., CMB) 121 is an opening or slot in the desktopconsole. The CMB houses the ACM and provides communication to and fromthe ACM. The CMB also provides mechanical protection and support to theACM. The CMB has a mechanical alignment mechanism for mating a portionof the ACM to the console. The CMB further has thermal heat dissipationsinks, electrical connection mechanisms, and the like. Some details ofthe ACM can be found in co-pending patent application Ser. Nos.09/149,882 and 09/149,548 filed Sep. 8, 1998, commonly assigned, andhereby incorporated by reference for all purposes.

In a specific embodiment, the present multiple computer module systemhas a peripheral console that has two or more computer bays that canreceive a removable computer module or ACM. Multiple computer modulesystem can function as a personal computer with only one ACM and theperipheral console. The second and additional ACM can be added later toincrease overall system performance and reliability. The ACM operatesindependently as self-contained computer, communicates with each otherthrough a high-speed serial communication and share most peripheraldevices within the peripheral console. Each ACM controls its independentgraphics subsystem and drives separate video output signals. A practicalimplementation is a dual ACM system. In a dual ACM system, two monitorscan be used to display the two ACMs' graphics outputs at the same time.For a single monitor, a RGB switch is used to switch between the videooutputs of the two ACMs and can be controlled by a command from theuser. Similarly, input devices (i.e. keyboard and mouse) are switchedbetween the two computer systems with a command from the user. Commandfrom the user can be in the form of either a dedicated key on thekeyboard or a special icon on the screen that the mouse can click on.

In most embodiments, the ACM includes an enclosure such as the onedescribed with the following components, which should not be limiting:

1) A CPU with cache memory;

2) Core logic device or means;

3) Main memory;

4) A single primary Hard Disk Drive (“HDD”) that has a security program;

5) Flash memory with system BIOS and programmable user password;

6) Operating System, application software, data files on primary HDD;

7) An interface device and connectors to peripheral console;

8) A software controllable mechanical lock, lock control means, andother accessories.

The ACM connects to a peripheral console with power supply, a displaydevice, an input device, and other elements. Some details of theseelements with the present system are described in more detail below. Ina dual ACM system, the primary ACM can connect directly to theperipheral board in the peripheral console. The second ACM can connecteither directly or indirectly to the peripheral board. For indirectconnection, a receptacle board is added to allow a cable connection tothe peripheral board. This is to facilitate the mechanical positioningof the second ACM inside the computer chassis. The receptacle boardapproach can even be used for the primary ACM if a high bandwidthperipheral bus, e.g. PCI Bus, is not connected from the primary ACM tothe peripheral board.

The shared peripheral console has a chassis and a motherboard thatconnects the following devices:

1) Input means, e.g. keyboard and mouse,

2) Display means, e.g. RGB monitor,

3) Add-on means, e.g. PCI add-on slots,

4) Two Computer Module Bays (CMB) with connectors to two ACMs,

5) A serial communication Hub controller that interfaces to serialcommunication controller of both ACMs,

6) Shared storage subsystem, e.g. Floppy drive, CDROM drive, DVD drive,or 2nd Hard Drive,

7) Communication device, e.g. modem,

8) Power supply, and others.

The computer bay is an opening in the peripheral console that receivesan ACM. CMB provides mechanical protection to ACM, mechanical alignmentfor connector mating, mechanical locking system to prevent theft andaccidental removal, and connectors at the end of the opening forconnecting to ACM. The interface bus between ACM and the peripheralconsole has a video bus, peripheral connections, serial communicationconnection, control signals and power connection. Video bus includesvideo output of graphics devices, i.e. analog RGB and control signalsfor monitor. Power connection supplies the power for ACM.

An implementation of peripheral sharing is the use of Ethernetcontrollers to bridge the communication between the two ACMs. Some ofthe peripheral devices residing in the peripheral console are shown inthe simplified diagram of FIG. 2. As shown, the diagram is merely anillustration which should not limit the scope of the claims herein. Oneof ordinary skill in the art would recognize many other variations,alternatives, and modifications. As shown, a primary ACM 203 isconnected to PCI peripheral devices in the peripheral console throughthe PCI bus 225 that passes through the connection between primary ACM203 and peripheral console 201. As shown, ACM has a CPU module 207coupled to the PCI bus through a North Bridge 211.

The CPU module can use a suitable microprocessing unit, microcontroller,digital signal processor, and the like. In a specific embodiment, theCPU module uses, for example, a 400 MHz Pentium II microprocessor modulefrom Intel Corporation and like microprocessors from AMD Corporation,Cyrix Corporation (now National Semiconductor Corporation), and others.In other aspects, the microprocessor can be one such as the CompaqComputer Corporation Alpha Chip, Apple Computer Corporation PowerPC G3processor, and the like. Further, higher speed processors arecontemplated in other embodiments as technology increases in the future.

In the CPU module, peripheral controller 213 is coupled to BIOS/flashmemory 217. Additionally, the peripheral controller is coupled to aclock control logic, a configuration signal, and a peripheral bus. TheACM has the hard drive module 215. Among other elements, the ACMincludes north bridge 215, graphics subsystem 223 (e.g., graphicsaccelerator, graphics memory), an IDE controller, and other components.Adjacent to and in parallel alignment with the hard drive module 215 isthe PCI bus. In a specific embodiment, North Bridge unit 211 oftencouples to a computer memory 209, to the graphics subsystem, and to theperipheral controller via the PCI bus. Graphics subsystem typicallycouples to a graphics memory, and other elements. IDE controllergenerally supports and provides timing signals necessary for the IDEbus. In the present embodiment, the IDE controller is embodied as partof a P114XE controller from Intel, for example. Other types of busesthan IDE are contemplated, for example EIDE, SCSI, 1394, and the like inalternative embodiments of the present invention.

The hard drive module or mass storage unit 215 typically includes acomputer operating system, application software program files, datafiles, and the like. In a specific embodiment, the computer operatingsystem may be the Windows98 operating system from Microsoft Corporationof Redmond Wash. Other operating systems, such as WindowsNT, MacOS8,Unix, and the like are also contemplated in alternative embodiments ofthe present invention. Further, some typical application softwareprograms can include Office98 by Microsoft Corporation, Corel PerfectSuite by Corel, and others. Hard disk module 215 includes a hard diskdrive. The hard disk drive, however, can also be replaced by removablehard disk drives, read/write CD ROMs, flash memory, floppy disk drives,and the like. A small form factor, for example 2.5″, is currentlycontemplated; however, other form factors, such as PC card, and the likeare also contemplated. Mass storage unit 240 may also support otherinterfaces than IDE.

Among other features, the computer system includes an ACM with securityprotection.

The ACM also has a network controller, which can be an Ethernetcontroller 219, which is coupled to the North Bridge through the PCIbus. The North Bridge is coupled to the CPU. The Ethernet controller canbe a 10/100 Base, such as Intel's 82559 or the like. Other types ofnetwork connection devices can also be used. For example, the inventioncan use Gbit Ethernet 1394, and USB 2.0. The network controller couplesto a hub 233 in the console, which includes shared peripheral system201.

Also shown is the second ACM 205. The second ACM has the same or similarcomponents as the first ACM. Here, like reference numerals have beenused for easy cross-referencing, but is not intended to be limiting. Insome embodiments, the secondary ACM is not connected to the PCI bus inthe peripheral console directly. The secondary ACM 219 accessesperipheral devices controlled by the primary ACM through the Ethernetconnection to the primary ACM, e.g. CD-ROM, or PCI modem. Theimplementation is not restricted to Ethernet serial communication andcan use other high-speed serial communication such as USB 2.0, and 1394.The Ethernet hub is coupled to an external output port 235, whichconnects to an external network.

The primary hard disk drive in each ACM can be accessed by the other ACMas sharable hard drive through the Ethernet connection. This allows theeasy sharing of files between the two independent computer modules. TheEthernet Hub Controller provides the high-speed communication functionbetween the two computer modules. Ethernet data bandwidth of 100Mbit/sec allows fast data communication between the two computermodules. The secondary ACM access peripheral devices of the primary ACMthrough the network connection provided by Ethernet link. The operatingsystem, e.g. Windows98, provides the sharing of resources between thetwo ACMs. In some embodiments, critical data in one ACM can be backed upinto the other ACM.

The Ethernet hub also couples to PCI bus 239, which connects to PCIdevices 241, 243, e.g., modem, SCSI controller. A flash memory 242 canalso be coupled to the PCI bus. The flash memory can store passwords andsecurity information, such as those implementations described in U.S.Ser. No. 09/183,493, which is commonly owned, and hereby incorporated byreference. The hub 233 also couples to an I/O control 237, whichconnects to keyboard/mouse switch 245, which couples to keyboard/mouse247. Optionally, the keyboard/mouse switch also couples to a secondkeyboard/house 259 via PS2 or USB signal line 251. The keyboard/mouseswitch has at least a first state and a second state, which allowoperation of respectively multiple keyboards or a single keyboard. Theswitch also couples to each I/O controller 221 in each ACM via lines253, 255. The I/O control 237 also couples to an RGB switch 257, whichallows video signals to pass to the first monitor 259. Alternatively,the RGB switch couples to a second monitor 261. The RGB switch includesanalog video switches such as MAXIM's MAX4545.

The peripheral system 201 also has an independent power supply 231 foreach ACM. Each power supply provides power to each ACM. As merely anexample, the power supply is a MICRO ATX 150 W made by ENLIGHT, but canbe others. The power supply is connected or coupled to each ACM througha separate line, for example. The independent power supply allows forindependent operation of each ACM in some embodiments.

The above embodiments are described generally in terms of hardware andsoftware. It will be recognized, however, that the functionality of thehardware can be further combined or even separated. The functionality ofthe software can also be further combined or even separated. Hardwarecan be replaced, at times, with software. Software can be replaced, attimes, with hardware. Accordingly, the present embodiments should not beconstrued as limiting the scope of the claims here. One of ordinaryskill in the art would recognize other variations, modifications, andalternatives.

FIG. 3 is a simplified block diagram 300 of a computer system accordingto an alternative embodiment of the present invention. This diagram ismerely an example which should not limit the scope of the claims herein.One of ordinary skill in the art would recognize many other variations,modifications, and alternatives. Like reference numerals are used inthis Fig. as the previous Figs. for easy referencing, but are notintended to be limiting. As shown, each ACM includes common elements asthe previous Fig. A primary ACM 203 is connected to PCI peripheraldevices in the peripheral console through the PCI bus 225 that passesthrough the connection between primary ACM 203 and peripheral console201. As shown, ACM has a CPU module 207 coupled to the PCI bus through aNorth Bridge 211.

The CPU module can use a suitable microprocessing unit, microcontroller,digital signal processor, and the like. In a specific embodiment, theCPU module uses, for example, a 400 MHz Pentium II microprocessor modulefrom Intel Corporation and like microprocessors from AMD Corporation,Cyrix Corporation (now National Semiconductor Corporation), and others.In other aspects, the microprocessor can be one such as the CompaqComputer Corporation Alpha Chip, Apple Computer Corporation PowerPC G3processor, and the like. Further, higher speed processors arecontemplated in other embodiments as technology increases in the future.

In the CPU module, peripheral controller 213 is coupled to BIOS/flashmemory 217. Additionally, the peripheral controller is coupled to aclock control logic, a configuration signal, and a peripheral bus. TheACM has the hard drive module 215. Among other elements, the ACMincludes north bridge 215, graphics subsystem 223 (e.g., graphicsaccelerator, graphics memory), an IDE controller, and other components.Adjacent to and in parallel alignment with the hard drive module 215 isthe PCI bus. In a specific embodiment, North Bridge unit 211 oftencouples to a computer memory 209, to the graphics subsystem, and to theperipheral controller via the PCI bus. Graphics subsystem typicallycouples to a graphics memory, and other elements. IDE controllergenerally supports and provides timing signals necessary for the IDEbus. In the present embodiment, the IDE controller is embodied as partof a P114XE controller from Intel, for example. Other types of busesthan IDE are contemplated, for example EIDE, SCSI, 1394, and the like inalternative embodiments of the present invention.

The hard drive module or mass storage unit 215 typically includes acomputer operating system, application software program files, datafiles, and the like. In a specific embodiment, the computer operatingsystem may be the Windows98 operating system from Microsoft Corporationof Redmond Wash. Other operating systems, such as WindowsNT, MacOS8,Unix, and the like are also contemplated in alternative embodiments ofthe present invention. Further, some typical application softwareprograms can include Office98 by Microsoft Corporation, Corel PerfectSuite by Corel, and others. Hard disk module 215 includes a hard diskdrive. The hard disk drive, however, can also be replaced by removablehard disk drives, read/write CD ROMs, flash memory, floppy disk drives,and the like. A small form factor, for example 2.5″, is currentlycontemplated; however, other form factors, such as PC card, and the likeare also contemplated. Mass storage unit 240 may also support otherinterfaces than IDE.

Among other features, the computer system includes an ACM with securityprotection.

The ACM also has a network controller, which can be coupled to a serialport 302, which is coupled to the PCI bus in the ACM. The serial port iscoupled to the peripheral console through a serial controller 301 in theserial console. The serial controller is connected to PCI bus 239. Theserial controller is also coupled to a serial hub controller 303, whichis coupled to the PCI bus and a second ACM. In a specific embodiment, areceptacle board 310 is added to connect to the second ACM. The purposeof the receptacle board is to allow a cable connection 307 to theperipheral board 300. The cable connection is possible because thesignals needed to connect to the peripheral board can be limited tovideo, I/O, serial communication, and power. The serial communicationcontroller can be placed on the receptacle board and not in the ACM. Asshown, the serial bus controller couples to the PCI bus. The receptacleboard also couples to power, graphics subsystem, I/O controller, andother elements, which may be on a common bus. The overall operation ofthe present configuration is similar to the previous one except itoperates in serial communication mode.

The Dual ACM system can support different usage models:

1. One user using both ACMs concurrently with 1 or 2 monitors, and acommon keyboard/mouse.

2. Two users using the two separate ACMs at the same time with separatemonitors and keyboard/mouse. The 2 users share peripherals, e.g.,printer, CDROM, and others. The two users share external networking.

To support 1 monitor for both ACMs, a video switch in the peripheralconsole is used to switch between the video outputs of the two ACMs. Thesystem can be set to support either 1 monitor or 2-monitor mode. Theuser presses a special key on the keyboard or a special icon on thescreen to switch the screen display from one ACM to the other. This sameaction causes the keyboard and mouse connections to switch from one ACMto the other ACM.

A dual ACM system can save space, wiring, and cost for a 2-person PCsetup, with the added benefit that both PC systems can be accessed fromone user site for increased system performance if the other user is notusing the system. Files can be copied between the primary drive of bothsystem and provides protection against a single ACM failure. Softwareneeds to be developed to manage the concurrent use of two PC subsystems,the automatic sharing of selected files between the two systems, andfault tolerance.

The design with more than two computer modules can be implemented withthe use of multi-port, serial communication hub controller andmulti-port I/O switches. In one embodiment, a peripheral console hasfour computer bays for four separate computer modules. The computermodules communicate through a four port Ethernet hub. The video,keyboard, and mouse switch will cycle through the connection from eachcomputer module to the external monitor, keyboard, and mouse with a pushbutton sequentially. This embodiment is useful for a server thatperforms different functions concurrently, e.g. email, applicationhosting, web hosting, firewall, etc.

The above embodiments are described generally in terms of hardware andsoftware. It will be recognized, however, that the functionality of thehardware can be further combined or even separated. The functionality ofthe software can also be further combined or even separated. Hardwarecan be replaced, at times, with software. Software can be replaced, attimes, with hardware. Accordingly, the present embodiments should not beconstrued as limiting the scope of the claims here. One of ordinaryskill in the an would recognize other variations, modifications, andalternatives.

FIG. 4 is a simplified diagram of a method according to an embodiment ofthe present invention. This diagram is merely an example which shouldnot limit the scope of the claims herein. One of ordinary skill in theart would recognize many other variations, modifications, andalternatives. The present diagram illustrates an automatic file backupprocedure from one computer module to the other. As shown, a userselects (step 401) a certain file in one of the computer module forautomatic backup. Next, the method determines if another module isavailable, step 403. If so, the method in the originating modulerequests the other computer module to create (step 405) backup file.Alternatively, the method alerts the user of the missing ormalfunctioning module, step 429. The method then has the user try later431, once the missing or malfunctioning module has been replaced orrepaired. Next, the method determines if there is sufficient storageavailable in the other computer module for the backup files. If so, themethod goes to the next step. (Alternatively, the method prompts (step433) a message to the user indicating that the storage is full.) In thenext step, the method stores the backup file in memory of the othermodule. After the backup file has been successfully created (step 409),the software in the originating ACM sets a timer to check (step 411) forfile modification via branches 423, 427 through continue, step 425process. If a file selected for backup has been modified (step 415),then the file is automatically back up to the other ACM again, step 417.Alternatively, the method returns to step 411 through branch 421.

The above embodiments are described generally in terms of hardware andsoftware. It will be recognized, however, that the functionality of thehardware can be further combined or even separated. The functionality ofthe software can also be further combined or even separated. Hardwarecan be replaced, at times, with software. Software can be replaced, attimes, with hardware. Accordingly, the present embodiments should not beconstrued as limiting the scope of the claims here. One of ordinaryskill in the art would recognize other variations, modifications, andalternatives.

FIG. 6 is a block diagram of one embodiment of a computer system 600using the interface of the present invention. Computer system 600includes an attached computer module (ACM) 605 and a peripheral console610, which are described in greater detail in the application of WilliamW. Y. Chu for “Personal Computer Peripheral Console With AttachedComputer Module” filed concurrently with the present application on Sep.8, 1998 and incorporated herein by reference. The ACM 605 and theperipheral console 610 are interfaced through an exchange interfacesystem (XIS) bus 615. The XIS bus 615 includes power bus 616, video bus617 and peripheral bus (XPBus) 618, which is also herein referred to asan interface channel. The power bus 616 transmits power between ACM 605and peripheral console 610. In a preferred embodiment power bus 616transmits power at voltage levels of 3.3 volts, 5 volts and 12 volts.Video bus 617 transmits video signals between the ACM 605 and theperipheral console 610. In a preferred embodiment, the video bus 617transmits analog Red Green Blue (RGB) video signals for color monitors,digital video signals (such as Video Electronics Standards Association(VESA) Plug and Display's Transition Minimized Differential Signaling(TMDS) signals for flat panel displays), and television (TV) and/orsuper video (S-video) signals. The XPBus 618 is coupled to hostinterface controller (HIC) 619 and to peripheral interface controller(PIC) 620, which is also sometimes referred to as a bay interfacecontroller.

In the embodiment shown in FIG. 6, HIC 619 is coupled to an integratedunit 621 that includes a CPU, a cache and a north bridge. In anotherembodiment, such as that shown in FIG. 7, the CPU 705 and north bridge710 are separate rather than integrated units.

In yet another embodiment, such as that shown in FIG. 8, the HIC and PICare integrated with the north and south bridges, respectively, such thatintegrated HIC and north bridge unit 805 includes an HIC and a northbridge, while integrated PIC and south bridge unit 810 includes a PICand a south bridge. FIG. 8A shows an attached computer module withintegrated CPU/NB/Graphics 815 and Integrated HIC/SB820. FIG. 8B showsan attached computer module with single chip 825 fully integrated: CPU,Cache, Core Logic, Graphics controller and Interface controller. In animplementation with South Bridge in Peripheral Console, FIG. 8C shows anexample of an attached computer module with Integrated CPU/NorthBridge/Graphics and Peripheral Console with Integrated PeripheralInterface Controller and South Bridge.

FIG. 9 is a more detailed block diagram of one embodiment of an HIC 905and a PIC 955 of the present invention. HIC 905 includes a peripheralcomponent interconnect (PCI) bus controller 910, an XPBus controller915, a phase lock loop (PLL) clock 920 and an input/output (IO) control925. Similarly, PIC 955 includes a PCI bus controller 960, an XPBuscontroller 965, a PLL clock 970 and an IO control 975. PCI buscontrollers 910 and 960 are coupled to the primary and secondary PCIbuses 930 and 980, respectively, and manage PCI transactions on theprimary and secondary PCI buses 930 and 980, respectively. Similarly,XPBus Controllers 915 and 965 are coupled to XPBus 990. XPBus controller915 drives the PCK line 991 and PD[0::3] and PCN lines 992 while XPBuscontroller 965 drives the PCKR lines 993, the PDR[0::3] and PCNR lines994 and the RESET# line 995.

PCI bus controller 910 receives PCI clock signals from the primary PCIbus 930 and is synchronized to the PCI clock. However, as indicated inFIG. 9, the XPBus controller 915 is asynchronous with the PCI buscontroller 910. Instead, the XPBus controller receives a clock signalfrom the PLL clock 920 and is synchronized therewith. PLL clock 920generates a clock signal independent of the PCI clock. The asynchronousoperation of the PCI bus and the XPBus allows the PCI Bus to change infrequency. for example as in a power down situation, without directlyaffecting the XPBus clocking. In the embodiment shown in FIG. 9, the PLLclock 920 generates a clock signal having a frequency of 66 MHz, whichis twice as large as the 33 MHz frequency of the PCI clock. (The clocksignal generated by the PLL clock may have a clock speed different from,including lower than, 66 MHz. For example, in another embodiment, whichis discussed in greater detail below, the PLL clock 920 generates aclock signal having a frequency of 132 MHz.)

The XPBus 990 operates at the clock speed generated by the PLL clock920. Therefore, PCK, the clock signal from the XPBus controller 915 toXPBus controller 965 has the same frequency as the clock signalgenerated by PLL clock 920. XPBus controller 965 receives the PCK signalafter it has been buffered and operates at the clock speed of PCK. Thebuffered version of the clock signal PCK is used to generate the clocksignal PCKR, the clock signal form the XPBus controller 965 to XPBuscontroller 915. Accordingly, PCKR also has the same frequency as thatgenerated by the PLL clock 920. The synchronous operation of PCK andPCKR provides for improved reliability in the system. In anotherembodiment, PCKR may be generated independently of PCK and may have afrequency different from that of PCK. It is to be noted that even whenPCKR is generated from PCK, the slew between PCK and PCKR cannot beguaranteed because of the unknown cable length used for the XPBus. For acable that is several feet long, the cable propagation delay alone canbe several nano seconds.

As indicated in FIG. 9, PLL clock 970 is asynchronous with the XPBuscontroller 965. Instead, PLL clock 970 independently generates a clocksignal that is used as a PCI clock signal on the secondary PCI bus 980.The secondary PCI bus 980 operates at the same clock speed as theprimary PCI bus 930, namely at a frequency of 33 MHz.

FIG. 10 is a detailed block diagram of one embodiment of the HIC of thepresent invention. As shown in FIG. 10, HIC 1000 comprises buscontroller 1010, translator 1020, transmitter 1030, receiver 1040, a PLL1050, an address/data multiplexer (A/D MUX) 1060, a read/writecontroller (RD/WR Cntl) 1070, a video serial to parallel converter 1080and a CPU control & general purpose input/output latch/driver (CPU CNTL& GPIO latch/driver) 1090.

HIC 1000 is coupled to an optional flash memory BIOS configuration unit1001. Flash memory unit 1001 stores basic input output system (BIOS) andPCI configuration information and supplies the BIOS and PCIconfiguration information to A/D MUX 1060 and RD/WR Control 1070, whichcontrol the programming, read, and write of flash memory unit 1001.

Bus controller 1010 is coupled to the host PCI bus which is alsoreferred to herein as the primary PCI bus, and manages PCI bustransactions on the host PCI bus. Bus controller 1010 includes a slave(target) unit 1011 and a master unit 1016. Both slave unit 1011 andmaster unit 1016 each include two first in first out (FIFO) buffers,which are preferably asynchronous with respect to each other since theinput and output of the two FIFOs in the master unit 1016 as well as thetwo FIFOs in the slave unit 1011 are clocked by different clocks, namelythe PCI clock and the PCK. Additionally, slave unit 1011 includesencoder 1022 and decoder 1023, while master unit 1016 includes encoder1027 and decoder 1028. The FIFOs 1012, 1013, 1017 and 1018 manage datatransfers between the host PCI bus and the XPBus, which in theembodiment shown in FIG. 10 operate at 33 MHz and 106 MHz, respectively.PCI address/data (AD) from the host PCI bus is entered into FIFOs 1012and 1017 before they are encoded by encoders 1022 and 1023. Encoders1022 and 1023 format the PCI address/data bits to a form more suitablefor parallel to serial conversion prior to transmittal on the XPBus.Similarly, address and data information from the receivers is decoded bydecoders 1023 and 1028 to a form more suitable for transmission on thehost PCI bus. Thereafter the decoded data and address information ispassed through FIFOs 1013 and 1018 prior to being transferred to thehost PCI bus. FIFOs 1012, 1013, 1017 and 1018, allow bus controller 1010to handle posted and delayed PCI transactions and to provide deepbuffering to store PCI transactions.

Bus controller 1010 also comprises slave read/write control (RD/WR Cntl)1014 and master read/write control (RD/WR Cntl) 1015. RD/WR controls1014 and 1015 are involved in the transfer of PCI control signalsbetween bus controller 1010 and the host PCI bus.

Bus controller 1010 is coupled to translator 1020. Translator 1020comprises encoders 1022 and 1027, decoders 1023 and 1028, controldecoder & separate data path unit 1024 and control encoder & merge datapath unit 1025. As discussed above encoders 1022 and 1027 are part ofslave data unit 1011 and master data unit 1016, respectively, receivePCI address and data information from FIFOs 1012 and 1017, respectively,and encode the PCI address and data information into a form moresuitable for parallel to serial conversion prior to transmittal on theXPBus. Similarly, decoders 1023 and 1028 are part of slave data unit1011 and master data unit 1016, respectively, and format address anddata information from receiver 1040 into a form more suitable fortransmission on the host PCI bus. Control encoder & merge data path unit1025 receives PCI control signals from the slave RD/WR control 1014 andmaster RD/WR control 1015. Additionally. control encoder & merge datapath unit 1025 receives control signals from CPU CNTL & GPIOlatch/driver 1090, which is coupled to the CPU and north bridge (notshown in FIG. 10). Control encoder & merge data path unit 1025 encodesPCI control signals as well as CPU control signals and north bridgesignals into control bits, merges these encoded control bits andtransmits the merged control bits to transmitter 1030, which thentransmits the control bits on the data lines PD0 to PD3 and control linePCN of the XPBus. Examples of control signals include PCI controlsignals and CPU control signals. A specific example of a control signalis FRAME# used in PCI buses. A control bit, on the other hand is a databit that represents a control signal. Control decoder & separate datapath unit 1024 receives control bits from receiver 1040 which receivescontrol bits on data lines PDR0 to PDR3 and control line PCNR of theXPBus. Control decoder & separate data path unit 1024 separates thecontrol bits it receives from receiver 1040 into PCI control signals,CPU control signals and north bridge signals, and decodes the controlbits into PCI control signals, CPU control signals, and north bridgesignals all of which meet the relevant timing constraints.

Transmitter 1030 receives multiplexed parallel address/data (AID) bitsand control bits from translator 1020 on the AD[31::0] out and the CNTLout lines, respectively. Transmitter 1030 also receives a clock signalfrom PLL 1050. PLL 1050 takes a reference input clock and generates PCKthat drives the XPBus. PCK is asynchronous with the PCI clock signal andoperates at 106 MHz, twice the speed of the PCI clock of 33 MHz. Thehigher speed is intended to accommodate at least some possible increasesin the operating speed of future PCI buses. As a result of the higherspeed, the XPBus may be used to interface two PCI or PCI-like busesoperating at 106 MHz rather than 33 MHz or having 104 rather than 32multiplexed address/data lines.

The multiplexed parallel A/D bits and some control bits input totransmitter 1030 are serialized by parallel to serial converters 1032 oftransmitter 1030 into 10 bit packets. These bit packets are then outputon data lines PD0 to PD3 of the XPBus. Other control bits are serializedby parallel to serial converter 1033 into 10 bit packets and send out oncontrol line PCN of the XPBus.

A 10× multiplier 1031 receives PCK, multiplies it by a factor of 10 andfeeds a clock signal 10 times greater than PCK into the parallel toserial converters 1032 and 1033. The parallel to serial converters 1032and 1033 perform bit shifting at 10 times the PCK rate to serialize theparallel bits into 10 bit packets. As the parallel to serial converters1032 and 1033 shift bits at 10 times the PCK rate, the bit rate for theserial bits output by the parallel to serial converters is 10 timeshigher than PCK rate, i.e., 1060 MHz. However, the rate at which datapackets are transmitted on the XPBus is the same as the PCK rate, i.e.,106 MHz. As the PCI buses operate at a clock and bit rate of 33 MHz, theXPBus has a clock rate that is twice as large and a bit rate per bitline (channel) that is 100 times as large as that of the PCI buses whichit interfaces.

Receiver 1040 receives serial bit packets on data lines PDR0 to PDR3 andcontrol line PCNR. Receiver 1040 also receives PCKR on the XPBus as wellas the clock signal PCK from PLL 1050. The synchronizer (SYNC) 1044 ofreceiver 1040 synchronizes the clock signal PCKR to the locallygenerated clock signal, PCK, in order to capture the bits received fromthe XPBus into PCK clock timing.

Serial to parallel converters 1042 convert the serial bit packetsreceived on lines PDR0 to PDR3 into parallel address/data and controlbits that are sent to decoders 1023 and 1028 and control decoder andseparate data path unit 1024, respectively. Serial to parallel converter1043 receives control bit packets from control line PCNR, converts themto parallel control bits and sends the parallel control bits to controldecoder & separate data path 1024.

A 10× multiplier 1041 receives PCKR, multiplies it by a factor of 10 andfeeds a clock signal 10 times greater than PCKR into the serial toparallel converters 1042 and 1043. Because the bits on PDR0 to PDR3 andPCNR are transmitted at a bit rate of 10 times the PCKR rate, the serialto parallel converters 1042 and 1043 perform bit shifting at 10 timesthe PCKR rate to convert the 10 bit packets into parallel bits. It is tobe noted that the rate at which bit packets are transmitted on the XPBusis the same as the PCKR rate, i.e., 106 MHz. The parallel data andcontrol bits are thereafter sent to decoders 1023 and 1028 by way of theAD[3::0] in line and to control decoder & separate data path unit 1024by way of CNTL in lines, respectively.

Reset control unit 1045 of HIC 1000 receives the signal RESET#, which isan independent system reset signal, on the reset line RESET#. Resetcontrol unit 1045 then transmits the reset signal to the CPU CNTL & GPIOlatch/driver unit 1090.

As may be noted from the above, the 32 line host and secondary PCI busesare interfaced by 10 XPBus lines (PD0, PD1, PD2, PD3, PCN, PDR0, PDR1,PDR2, PDR3, PCNR). Therefore, the interface channel, XPBus, of thepresent invention uses fewer lines than are contained in either of thebuses which it interfaces, namely the PCI buses. XPBus is able tointerface such PCI buses without backup delays because the XPBusoperates at a clock rate and a per line (channel) bit rate that arehigher than those of the PCI buses.

In addition to receiving a reset signal, the CPU CNTL & GPIOlatch/driver 1090 is responsible for latching input signals from the CPUand north bridge and sending the signals to the translator. It alsotakes decoded signals from the control decoder & separate data path unit1024 and drives the appropriate signals for the CPU and north bridge.

In the embodiment shown in FIG. 10, video serial to parallel converter1080 is included in HIC 1000. In another embodiment, video serial toparallel converter 1080 may be a separate unit from the HIC 1000. Videoserial to parallel converter 1080 receives serial video data on line VPDand a video clock signal VPCK from line VPCK of video bus 1081. It thenconverts the serial video data into 16 bit parallel video port data andthe appropriate video port control signals, which it transmits to thegraphics controller (not shown in FIG. 10) on the video port data[0::15] and video port control lines, respectively.

HIC 1000 handles the PCI bus control signals and control bits from theXPBus representing PCI control signals in the following ways:

1. HIC 1000 buffers clocked control signals from the host PCI bus,encodes them into control bits and sends the encoded control bits to theXPBus;

2. HIC 1000 manages the signal locally; and

3. HIC 1000 receives control bits from XPBus, translates the controlbits into PCI control signals and sends the PCI control signals to thehost PCI bus.

FIG. 11 is a detailed block diagram of one embodiment of the PIC of thepresent invention. PIC 1100 is nearly identical to HIC 1000 in itsfunction, except that HIC 1000 interfaces the host PCI bus to the XPBuswhile PIC 1100 interfaces the secondary PCI bus to the XPBus. Similarly,the components in PIC 1100 serve the same function as theircorresponding components in HIC 1000. Reference numbers for componentsin PIC 1100 have been selected such that a component in PIC 1100 and itscorresponding component in HIC 1000 have reference numbers that differby 500 and have the same two least significant digits. Thus for example,the bus controller in PIC 1100 is referenced as bus controller 1110while the bus controller in HIC 1000 is referenced as bus controller1010. As many of the elements in PIC 1100 serve the same functions asthose served by their corresponding elements in HIC 1000 and as thefunctions of the corresponding elements in HIC 1000 have been describedin detail above, the function of elements of PIC 1100 havingcorresponding elements in HIC 1000 will not be further described herein.Reference may be made to the above description of FIG. 10 for anunderstanding of the functions of the elements of PIC 1100 havingcorresponding elements in HIC 1000.

As suggested above, there are also differences between HIC 1000 and PIC1100. Some of the differences between HIC 1000 and PIC 1100 include thefollowing. First, receiver 1140 in PIC 1100, unlike receiver 1040 in HIC1000, does not contain a synchronization unit. As mentioned above, thesynchronization unit in HIC 1000 synchronizes the PCKR clock to the PCKclock locally generated by PLL 1050. PIC 1100 does not locally generatea PCK clock and therefore, it does not have a locally generated PCKclock with which to synchronize the PCK clock signal that it receivesfrom HIC 1000. Another difference between PIC 1100 and HIC 1000 is thefact that PIC 1100 contains a video parallel to serial converter 1189whereas HIC 1000 contains a video serial to parallel converter 1080.Video parallel to serial converter 1189 receives 16 bit parallel videocapture data and video control signals on the Video Port Data [0::15]and Video Port Control lines, respectively, from the video capturecircuit (not shown in FIG. 11) and converts them to a serial video datastream that is transmitted on the VPD line to the HIC. The video capturecircuit may be any type of video capture circuit that outputs a 16 bitparallel video capture data and video control signals. Anotherdifference lies in the fact that PIC 1100, unlike HIC 1000, contains aclock doubler 1182 to double the video clock rate of the video clocksignal that it receives. The doubled video clock rate is fed into videoparallel to serial converter 1182 through buffer 1183 and is sent toserial to parallel converter 1080 through buffer 1184. Additionally,reset control unit 1135 in PIC 1100 receives a reset signal from the CPUCNTL & GPIO latch/driver unit 1190 and transmits the reset signal on theRESET# line to the HIC 1000 whereas reset control unit 1045 of HIC 1000receives the reset signal and forwards it to its CPU CNTL & GPIOlatch/driver unit 1090 because, in the above embodiment, the resetsignal RESET# is unidirectionally sent from the PIC 1100 to the HIC1000.

Like HIC 1000, PIC 1100 handles the PCI bus control signals and controlbits from the XPBus representing PCI control signals in the followingways:

1. PIC 1100 buffers clocked control signals from the secondary PCI bus.encodes them and sends the encoded control bits to the XPBus;

2. PIC 1100 manages the signal locally; and

3. PIC 1100 receives control bits from XPBus, translates them into PCIcontrol signals and sends the PCI control signals to the secondary PCIbus.

PIC 1100 also supports a reference arbiter on the secondary PCI Bus tomanage the PCI signals REQ# and GNT#.

FIG. 12 is a table showing the symbols, signals, data rate anddescription of signals on the XPBus, where RTN indicates a ground (GND)reference. In the above tables, P&D stands for plug and display and is atrademark of the Video Electronics Standards Association (VESA) for thePlug and Display standard, DDC2:SCL and DDC2:SDA stand for the VESAdisplay data channel (DDC) standard 2 clock and data signals,respectively, SV stands for super video, V33 is 3.3 volts, and V5 is 5.0volts. TMDS stands for Transition Minimized Differential Signaling andis a trademark of Silicon Images and refers to their Panel Linktechnology, which is in turn a trademark for their LVDS technology. TMDSis used herein to refer to the Panel Link technology or technologiescompatible therewith.

FIG. 13 is a table showing the information transmitted on the XPBusduring two clock cycles of the XPBus in one embodiment of the presentinvention where 10 data bits are transmitted in each clock cycle of theXPBus. In FIG. 13, A00 to A31 represent 32 bits of PCI address A[31::0],D00 to D31 represent 32 bits of PCI data D[31::0], BS0 to BS3 represent4 bits of bus status data indicating the status of the XPBus, CM0# toCM3# represent 4 bits of PCI command information, BE0# to BE3# represent4 bits of PCI byte enable information, and CN0 to CN9 represent 10 bitsof control information sent in each clock cycle. As shown in FIG. 13,for each of lines PD0 to PD3, the 10 bit data packets contain one BSbit, one CM/BE bit, and eight AID bits. For the PCN line, the 10 bitdata packet contains 10 CN bits. The first clock cycle shown in FIG. 13comprises an address cycle in which 4 BS bits, 4 CM bits, 32 A bits and10 CN bits are sent. The second clock cycle comprises a data cycle inwhich 4 BS bits, 4 BE bits, 32 D bits and 10 CN bits are sent. The bitstransmitted on lines PD0 to PD3 represent 32 PCI AD[31::0] signals, 4PCI C/BE# [3::0] signals, and part of the function of PCI controlsignals, such as FRAME#, IRDY#, and TRDY#.

In the embodiment shown in FIG. 13, BS0 to BS3 are sent at the beginningof each clock cycle. The bus status bits indicate the following buscycle transactions: idle, address transfer, write data transfer, readdata transfer, switch XPBus direction, last data transfer, wait, andother cycles.

Bits representing signals transmitted between the CPU and South Bridgemay also be sent on the lines interconnecting the HIC and PIC, such aslines PCN and PCNR. For example, CPU interface signals such as CPUinterrupt (INTR), Address 20 Mask (A20M#), Non-Maskable Interrupt (NMI),System Management Interrupt (SMI#), and Stop Clock (STPCLK#), may betranslated into bit information and transmitted on the XPBus between theHIC and the PIC.

FIG. 14 is a table showing the information transmitted on the XPBusduring four clock cycles of the XPBus in another embodiment of thepresent invention where 10 data bits are transmitted in each clock cycleof the XPBus. In this embodiment, the XPBus clock rate is twice as largeas the PCI clock rate. This allows sending data and address bits everyother XPBus cycle. As can be seen in FIG. 14, there are no address ordata bits transmitted during the second or fourth XPBus clock cycle. Thefact that the XPBus clock rate is higher than the PCI clock rate allowsfor compatibility of the XPBus with possible future expansions in theperformance of PCI bus to higher data transfer and clock rates.

In the embodiment shown in FIG. 14, there are 18 control bits, CN0 toCN17, transmitted in every two XPBus clock cycles. The first bittransmitted on the control line in each XPBus clock cycle indicateswhether control bits CN0 to CN8 or control bits CN9 to CN17 will betransmitted in that cycle. A zero sent at the beginning of a cycle onthe control line indicates that CN0 to CN8 will be transmitted duringthat cycle, whereas a one sent at the beginning of a cycle on thecontrol line indicates that CN9 to CN17 will be transmitted during thatcycle. These bits also indicate the presence or absence of data andaddress bits during that cycle. A zero indicates that address or databits will be transmitted during that cycle whereas a one indicates thatno address or data bits will be transmitted during that cycle.

In one embodiment, BS0 and BS1 are used to encode the PCI signals FRAME#and IRDY#, respectively. Additionally, in one embodiment, BS2 and BS3are used to indicate the clock speed of the computer bus interface andthe type of computer bus interface, respectively. For example. BS2 valueof zero may indicate that a 33 MHz PCI bus of 32 bits is used whereas aBS2 value of one may indicate that a 66 MHz PCI bus of 32 bits is used.Similarly, a BS3 value of zero may indicated that a PCI bus is usedwhereas a BS3 value of one may indicated that another computer interfacebus, such as an Institute of Electronics & Electrical Engineers (IEEE)1394 bus, is used.

FIG. 15 is a schematic diagram of lines PCK, PD0 to PD3, and PCN. Theselines are unidirectional LVDS lines for transmitting clock signals andbits such as those shown in FIGS. 13 and 14 from the HIC to the PIC. Thebits on the PD0 to PD3 and the PCN lines are sent synchronously withinevery clock cycle of the PCK. Another set of lines, namely PCKR, PDR0 toPDR3, and PCNR, are used to transmit clock signals and bits from the PICto HIC. The lines used for transmitting information from the PIC to theHIC have the same structure as those shown in FIG. 15, except that theytransmit data in a direction opposite to that in which the lines shownin FIG. 15 transmit data. In other words they transmit information fromthe PIC to the HIC. The bits on the PDR0 to PDR3 and the PCNR lines aresent synchronously within every clock cycle of the PCKR. Some of theexamples of control information that may be sent in the reversedirection, i.e., on PCNR line, include a request to switch data busdirection because of a pending operation (such as read data available),a control signal change in the target requiring communication in thereverse direction, target busy, and transmission error detected.

FIG. 28 is a block diagram of another embodiment of the HIC and PIC ofthe present invention and the interface therebetween. One importantdifference between the XPBuses shown in FIGS. 9 and 28 is the fact thatunlike the XPBus of FIG. 9 and the XPBus of FIG. 28 does not havecontrol lines PCN and PCNR. Another difference lies in the fact that theXPBus of FIG. 28 has two dedicated reset lines RSTEH# and RSTEP# insteadof only one as is the case for the XPBus of FIG. 9 RSTEH# and RSTEP# areunidirectional reset and error condition signal lines that transmit areset and error condition signal from the host PCI to the peripheral PCIand fro the peripheral PCI to host PCT, respectively.

In one embodiment, each of reset lines RSTEH#, RSTEP#, and RESET# (shownin FIG. 9), is preferably a non-differential signal line consisting ofone physical line. In other embodiments, one or more of the above linesmay be a differential signal line having more than one physical line.

FIG. 29 shows a detailed block diagram of the HIC shown in FIG. 28. HIC2900 shown in FIG. 29 is, other than for a few differences, identical toHIC 1000 shown in FIG. 10. Accordingly, reference numbers for componentsin HIC 2900 have been selected such that a component in HIC 2900 and itscorresponding component in HIC 1000, have reference numbers that differby 1900 and have the same two least significant digits. One of thedifferences between HIC 2900 and HIC 1000 is the fact that, unlike HIC1000, HIC 2900 does not have a parallel to serial converter or a serialto parallel converter dedicated exclusively to CNTL out and CNTL insignals, respectively. This is due to the fact that XPBus for HIC 2900does not contain a PCN or PCNR line. Another important differencebetween HIC 2900 and HIC 1000 is the fact that HIC 2900, unlike HIC1000, has two reset lines, RSTEP# and RSTEH#, instead of only one resetline. Reset line RSTEP# is coupled to Reset & XPBus Parity Error ControlUnit 2936 which receives, on the reset line RSTEP#, a reset signal and aparity error signal generated by the PIC, sends a reset signal to theCPU CNTL & GPIO latch/driver 2990, and controls retransmission of bitsfrom the parallel to serial converters 2932. Reset & XPBus Parity ErrorDetection and Control Unit 2946 takes bits from serial to parallelconverters 2942, performs a parity check to detect any transmissionerror, and sends reset and parity error signals to the PIC on the resetline RSTEH#. The reset and parity error signals may be distinguished bydifferent signal patterns and/or different signal durations. In the tworeset line system, the reset and error parity signals are transmitted onthe same line and it is possible to send a parity error confirmationsignal on one line while receiving a reset signal on the other line.Because HIC 2900 provides for parity error detection, the parallel toserial converters 2932 include buffers. The buffers in parallel toserial converters 2932 store previously transmitted bits (e.g., thosetransmitted within the previous two clock cycles) for retransmission iftransmission error is detected and a parity error signal is received online RSTEP#. It is to be noted that parallel to serial converters 1032do not contain buffers such as those obtained in parallel to serialconverters 2932 for purposes of retransmission since HIC 1000 does notprovide for parity error signal detection. Yet another differencebetween HIC 1000 and HIC 2900 is the fact that in HIC 2900 clockmultipliers 2931 and 2941 multiply the PCK and PCKR clocks,respectively, by a factor of 6 rather than 10 because the XPBus coupledto HIC 2900 transmits six bit packets instead of ten bit packets duringeach XPBus clock cycle. Sending a smaller number of bits per XPBus clockcycle provides the benefit of improving synchronization between the datalatching clock output by clock multipliers 2931 and 2941 and the XPBusclocks, PCK and PCKR. In another embodiment, one may send 5 or someother number of bits per XPBUs clock cycle. As mentioned above, theremaining elements in HIC 2900 are identical to those in HIC 1000 andreference to the description of the elements in HIC 1000 may be made tounderstand the function of the corresponding elements in HIC 2900.

FIG. 30 shows a detailed block diagram of the PIC shown in FIG. 28. PIC3000 is, but for the differences discussed above between HICs 2900 and1000, identical to PIC 1100. Accordingly, reference numbers forcomponents in PIC 3000 have been selected such that a component in PIC3000 and its corresponding component in PIC 1100 have reference numbersthat differ by 1900 and have the same two least significant digits.Reference may be made to (1) the description above of PIC 1100 and (2)the discussion above of the differences between HICs 1000 and 2900 for afull understanding of the elements of PIC 3000. With respect to Reset &XPBus Parity Error Control Unit 3036 and Reset & XPBus Parity ErrorDetection & Control Unit 3046, it is to be noted that they serve thesame type of functions as those performed by Reset & XPBus Parity ErrorControl Unit 2936 and Reset & XPBus Parity Error Detection & ControlUnit 2946, respectively, except that Reset & XPBus Parity Error ControlUnit 3036 receives a reset and parity error signal on reset line RSTEH#instead of RSTEP# and Reset & XPBus Parity Error Detection & ControlUnit 3046 sends a reset and parity error signal on RSTEP# instead ofRSTEH#.

FIG. 31 is a schematic diagram of the lines PCK and PD0 to PD3. Theselines are unidirectional LVDS lines for transmitting signals from HIC2900 to PIC 3000. Another set of lines, namely PCKR and PDR0 to PDR3,are used to transmit clock signals and bits from PIC 3000 to HIC-2900.

The XPBus which includes lines PCK, PD0 to PD3, PCN, PCKR, PDR0 to PDR3,and PCNR, has two sets of unidirectional lines transmitting clocksignals and bits in opposite directions. The first set of unidirectionallines includes PCK, PD0 to PD3, and PCN. The second set ofunidirectional lines includes PCKR, PDR0 to PDR3, and PCNR. Each ofthese unidirectional set of lines is a point-to-point bus with a fixedtransmitter and receiver, or in other words a fixed master and slavebus. For the first set of unidirectional lines, the HIC is a fixedtransmitter/master whereas the PIC is a fixed receiver/slave. For thesecond set of unidirectional lines, the PIC is a fixedtransmitter/master whereas the HIC is a fixed receiver/slave. The LVDSlines of XPBus, a cable friendly and remote system I/O bus, transmitfixed length data packets within a clock cycle.

The XPBus lines, PD0 to PD3, PCN, PDR0 to PDR3 and PCNR, and the videodata and clock lines, VPD and VPCK, are not limited to being LVDS lines,as they may be other forms of bit based lines. For example, in anotherembodiment, the XPBus lines may be IEEE 1394 lines.

It is to be noted that although each of the lines PCK, PD0 to PD3, PCN,PCKR, PDR0 to PDR3, PCNR, VPCK, and VPD is referred to as a line, in thesingular rather than plural. each such line may contain more than onephysical line. For example, in the embodiment shown in FIG. 23, each oflines PCK, PD0 to PD3 and PCN includes two physical lines between eachdriver and its corresponding receiver. The term line, when not directlypreceded by the terms physical or conductive, is herein usedinterchangeably with a signal or bit channel which may consist of one ormore physical lines for transmitting a signal. In the case ofnon-differential signal lines, generally only one physical line is usedto transmit one signal. However, in the case of differential signallines, a pair of physical lines is used to transmit one signal. Forexample, a bit line or bit channel in an LVDS or IEEE 1394 interfaceconsists of a pair of physical lines which together transmit a signal.

A bit based line (i.e., a bit line) is a line for transmitting serialbits. Bit based lines typically transmit bit packets and use a serialdata packet protocol. Examples of bit lines include an LVDS line, anIEEE 1394 line, and a Universal Serial Bus (USB) line.

FIG. 27 is a table showing different types of first nibbles and theircorresponding data packet types. The reserved data packet types can beused to support non-PCI bus transactions, e.g., USB transactions. Thebits sent in the first nibble of each data packet indicate the type ofthat data packet.

FIG. 16 is a table showing the names, types, number of pins dedicatedto, and the description of the primary bus PCI signals. The pinsrepresent those between the host PCI bus and the HIC.

FIG. 17 is a block diagram of the components in one computer systememploying the present invention. The computer system comprises anattached computer module (ACM), a peripheral console (PCON), and theinterconnection apparatus between them. The ACM includes the centralprocessing unit (CPU) 1710, system memory 1720, high performance devices1750, primary mass storage 1730, and related interface and supportcircuitry 1740. The PCON includes primary display 1810, primary input1820, secondary mass storage 1750, other devices 1860, expansion slots1870, the primary power supply 1830, and related interface and supportcircuitry 1840. The interconnection apparatus 1900 includes circuitry toconvey power and operational signals between the ACM and PCON.

Within the ACM 1700, the CPU 1710 executes instructions and manipulatesdata stored in the system memory. The CPU 1710 and system memory 1720represent the user's core computing power. The core computing power mayalso include high performance devices 1750 such as advanced graphicsprocessor chips that greatly increase overall system performance andwhich, because of their speed, need to be located close to the CPU. Theprimary mass storage 1730 contains persistent copies of the operatingsystem software, application software, configuration data, and userdata. The software and data stored in the primary mass storage devicerepresent the user's computing environment. Interface and supportcircuitry 1740 primarily includes interface chips and signal busses thatinterconnect the CPU, system memory, high performance devices, andprimary mass storage. The interface and support circuitry also connectsACM-resident components with the ACM-to-PCON interconnection apparatusas needed.

Within the PCON 1800, the primary display component 1810 may include anintegrated display device or connection circuitry for an externaldisplay device. This primary display device may be, for example, an LCD,plasma, or CRT display screen used to display text and graphics to theuser for interaction with the operating system and application software.The primary display component is the primary output of the computersystem, i.e., the paramount vehicle by which programs executing on theCPU can communicate toward the user.

The primary input component 1820 of the PCON may include an integratedinput device or connection circuitry for attachment to an external inputdevice. The primary input may be, for example, a keyboard, touch screen,keypad, mouse, trackball, digitizing pad, or some combination thereof toenable the user to interact with the operating system and applicationsoftware. The primary input component is the paramount vehicle by whichprograms executing on the CPU receive signals from the user.

The PCON may contain secondary mass storage 1850 to provide additionalhigh capacity storage for data and software. Secondary mass storage mayhave fixed or removable media and may include, for example, devices suchas diskette drives, hard disks, CD-ROM drives, DVD drives, and tapedrives.

The PCON may be enhanced with additional capability through the use ofintegrated “Other Devices” 1860 or add-on cards inserted into the PCON'sexpansion slots 1870. Examples of additional capability include soundgenerators, LAN connections, and modems. Interface and support circuitry1840 primarily includes interface chips, driver chips, and signal bussesthat interconnect the other components within the PCON. The interfaceand support circuitry also connects PCON-resident components with theACM-to-PCON interconnection apparatus as needed.

Importantly, the PCON houses the primary power supply 1830. The primarypower supply has sufficient capacity to power both the PCON and the ACM1700 for normal operation. Note that the ACM may include a secondary“power supply” in the form, for example, of a small battery. Such apower supply would be included in the ACM to maintain, for example, atime-of-day clock, configuration settings when the ACM is not attachedto a PCON, or machine state when moving an active ACM immediately fromone PCON to another. The total energy stored in such a battery would,however, be insufficient to sustain operation of the CPU at its ratedspeed, along with the memory and primary mass storage, for more than afraction of an hour, if the battery were able to deliver the requiredlevel of electrical current at all.

FIG. 18 is a block diagram of an attached computing module (ACM) 1700.The physical ACM package 1700 contains the ACM functional components1701 and the ACM side of the ACM-to-PCON Interconnection 1900. The ACM1701 comprises a CPU component 1710, a system memory component 1720, aprimary mass storage component 1730, a high performance devicescomponents 1750, and an interface and support component 1740.

The ACM side of the ACM-to-PCON Interconnection 1900 comprises a HostInterface Controller (HIC) component 1920 and an ACM connector component1930. The HIC 1920 and connector 1930 components couple the ACMfunctional components 1700 with the signals of an ACM-to-PCON interfacebus 1910 used to operatively connect an ACM with a PCON. The ACM-to-PCONinterface bus 1910 comprises conveyance for electrical power 1914 andsignals for a peripheral bus 1912, video 1916, video port 1917, andconsole type 1918. The preferred ACM-to-PCON Interconnection 1900 isdescribed in detail in a companion U.S. patent application Ser. No.09/149,882, entitled “A Communication Channel and Interface Devices forBridging Computer Interface Buses,” by the same inventor, filed on thesame day herewith, and hereby incorporated by reference. The preferredACM-to-PCON interconnection 1900 includes circuitry to transmit andreceive parallel bus information from multiple signal paths as a serialbit stream on a single signal path. This reduces the number of physicalsignal paths required to traverse the interconnection 1900. Further,employing low-voltage differential signaling (LVDS) on the bit streamdata paths provides very reliable, high-speed transmission acrosscables. This represents a further advantage of the present invention.

The CPU component 1710 of the ACM functional circuitry 1701 of thepresently described embodiment comprises a microprocessor 1712, which isthe chief component of the personal computer system, power supplyconnection point 1713, and cache memory 1714 tightly coupled to themicroprocessor 1712 by the CPU-to-cache bus 1714 comprising signal pathsfor address, data. and control information. The microprocessor 1712 ofthis embodiment is one of the models from the Pentium II family ofprocessors from Intel Corporation. Microprocessor 1712 receiveselectrical power from power bus 1768 via connection point 1713.Microprocessor 1712 couples to the Host Interface Controller (HIC) 1920via CPU-to-HIC bus 1763 comprising signal paths to exchange controlinformation such as an interrupt request. Microprocessor 1712 alsocouples to CPU Bridge 1746 via CPU main bus 1764 comprising signal pathsfor address, data, and control information.

The CPU Bridge component 1746 of the interface and support circuitry1740 operates to couple the high speed CPU main bus 1764 to specialtybuses of varying speeds and capability that connect other computercomponents. The CPU Bridge of the presently described embodimentincorporates memory controller circuitry, advanced graphics processorsupport circuitry, and a general, industry-standard PCI bus controllerin a single package. A CPU Bridge 1746 such as the 82443LX PCI/AGPController from Intel Corporation may be used.

The system memory component 1720 of the ACM functional circuitry 1701 inthe present embodiment comprises main system memory (RAM) 1722, BIOSmemory 1724, and flash memory 1726. The system memory 1720 is used tocontain data and instructions that are directly addressable by the CPU.The RAM 1722 comprises volatile memory devices such as DRAM or SDRAMmemory chips that do not retain their stored contents when power isremoved. This form of memory represents the largest proportion of totalsystem memory 1720 capacity. The BIOS memory 1724 comprises non-volatilememory devices such as ROM or EPROM memory chips that retain theirstored contents regardless of the application of power and are read-onlymemory under normal operating conditions. The BIOS memory 1724 stores,for example, start-up instructions for the microprocessor 1712 and setsof instructions for rudimentary input/output tasks. The flash memory1726 comprises non-volatile memory devices that retain their storedcontents regardless of the application of power. Unlike the BIOSnon-volatile memory, however, the stored contents of the flash memory1726 are easily changed under normal operating conditions. The flashmemory 1726 may be used to store status and configuration data, such assecurity identifiers or ACM specifications like the speed of themicroprocessor 1712. Some embodiments may combine the BIOS functionsinto the flash memory device, thus permitting BIOS contents to berewritten, improving field upgradability.

The main system memory (RAM) 1722 is coupled to memory controllercircuitry resident within the CPU Bridge 1746 via direct memory bus1765. The BIOS 1724 and flash memory 1726 are coupled to HIC 1920 viaswitched memory bus 1766. This permits the BIOS 1724 and flash 1726memories to be accessed by circuitry in the HIC 1920 or other circuitryconnected thereto. The direct memory bus 1765 and the switch memory bus1766 each comprises conductors to convey signals for data, address, andcontrol information.

The primary mass storage component 1730 of the ACM functional circuitry1701 in the present embodiment comprises a compact hard disk drive withan industry-standard, IDE interface. The hard disk drive (HDD) 1732 hasa formatted storage capacity sufficient to contain an operating systemfor the computer, application software desired by the user, and relateduser configuration and operating parameter data. The HDD 1732 in thepresent embodiment serves as the “boot” device for the personal computerfrom which the operating system is loaded into RAM 1722 by the start-upprogram stored in the BIOS 1724.

The present HDD 1732 has a capacity of approximately 2,000 megabytes toprovide adequate storage for common software configurations andreasonable space for user data. One example of a common softwareconfiguration includes the Windows 95 operating system from MicrosoftCorporation, a word processing program, a spreadsheet program, apresentation graphics program, a database program, an email program, anda web browser such as Navigator from Netscape Corporation. The hard disk1732 stores program and data files for each software component,including files distributed by the vendor as well as files created orupdated by operation of the software after it is installed. For example,a word processor program may maintain information about a user'sidentity and latest preferences in an operating system registry file.Or, for example, the web browser may maintain a file of the user'sfavorite web sites or most recently viewed web pages. An HDD with 2000megabyte capacity is readily available in the small size of hard disk(e.g., 2.5-inch or 3.5-inch) to minimize the space required within theACM for the primary mass storage device 1730.

The HDD 1732 is coupled to IDE controller circuitry 1748 via IDE bus1772. The IDE controller circuitry 1748 is coupled to the CPU Bridge1746 via the Host PCI bus 1767. IDE controllers and busses, and the PCIbus are well known and understood in the industry. The above componentsoperate together to couple the hard disk drive 1732 to themicroprocessor 1712.

The high performance devices component 1750 of the ACM functionalcircuitry 1701 in the present embodiment comprises an Advanced GraphicsProcessor (AGP) 1752. The Model 740 Graphics Device froth IntelCorporation may be used in the present embodiment as the AGP.

Increases in computer screen size, graphics resolution, color depth, andvisual motion frame rates, used by operating system and applicationsoftware alike, have increased the computing power required to generateand maintain computer screen displays. An AGP removes a substantialportion of the graphics computing burden from the CPU to the specializedhigh-performance processor, but a high level of interaction between theCPU and the specialized processor is nonetheless required. To maximizethe effective contribution of having a specialized processor in thepresently described embodiment, the AGP 1752 is located in the ACM 1700,where it is in close proximity to the microprocessor 1712. The AGP 1752is coupled to the microprocessor 1712 via the advanced graphics port bus1773 of the CPU Bridge 1746. The visual display signal generated by theAGP are conveyed toward actual display devices at the peripheral console(PCON) via video signal bus 1770. Video information from a sourceexternal to the ACM and appearing as video port signals 1917 may beconveyed to the AGP 1752 via video port signal path 1771.

Other types of high performance components may be included in differentACM configurations. For example, an interface to an extremely high speeddata communication facility may be desirable in some future computerwhere CPU-to-network interaction is of comparable intensity to today'sCPU-to-graphics interaction. Because such high performance componentstend to be high in cost, their inclusion in the ACM is desirable.Inclusion of high cost, high performance components in the ACMconcentrates a user's core computing power and environment in a portablepackage. This represents a further advantage of the invention.

The interface and support component 1740 of the ACM functional circuitry1701 in the present embodiment comprises circuitry for power regulation1742, clocking 1744, CPU Bridge 1746, IDE controller 1748, and signalconveyance paths 1761-1774. The CPU Bridge 1746 couples the CPUcomponent 1710 of the ACM 1700 with the other components of the ACM1720-1750 and the CPU-to-PCON Interconnection 1900. The CPU Bridge 1746and IDE controller 1748 have already been discussed. Power regulationcircuitry 1742 receives electrical power via the electrical powerconduction path 1914 of the CPU-to-PCON Interconnection 1900, conditionsand distributes it to the other circuitry in the ACM using powerdistribution bus 1768. Such regulation and distribution is well knownand understood in the art.

Clocking circuitry 1744 generates clock signals for distribution toother components within the ACM 1700 that require a timing andsynchronization clock source. The CPU 1710 is one such component. Often,the total power dissipated by a CPU is directly proportional to thefrequency of its main clock signal. The presently described embodimentof the ACM 1700 includes circuitry that can vary the frequency of themain CPU clock signal conveyed to the CPU via signal path 1762, inresponse to a signal received from the host interface controller (HIC)1920 via signal path 1761. The generation and variable frequency controlof clocking signals is well understood in the art. By varying thefrequency, the power consumption of the CPU (and thus the entire ACM)can be varied.

The variable clock rate generation may be exploited to match the CPUpower consumption to the available electrical power. Circuitry in thehost interface controller (HIC) 1920 of the presently describedembodiment adjusts the frequency control signal sent via signal path1761 to the clocking circuitry 1744, based on the “console type”information signal 1918 conveyed from the peripheral console (PCON) bythe CPU-to-PCON interconnection 1900. In this arrangement, the consoletype signal originating from a desktop PCON would result in thegeneration of a maximum speed CPU clock. The desktop PCON, presumablyhas unlimited power from an electrical wall outlet and does not need tosacrifice speed for power conservation. The console type signaloriginating from a notebook PCON would, however, result in thegeneration of a CPU clock speed reduced from the maximum in order toconserve battery power and extend the duration of computer operationobtained from the energy stored in the battery. The console type signaloriginating from a notepad PCON would result in the generation of a CPUclock speed reduced further yet, the notepad PCON presumably havingsmaller batteries than the notebook PCON. Inclusion of control signalsand circuitry to affect a CPU clock signal varying in frequencyaccording to characteristics of the PCON to which the ACM is connectedfacilitates the movement of the user's core computing power andenvironment to different work settings, which is a further advantage ofthe present invention.

FIG. 19 illustrates an external view of one embodiment of an ACM. Thecase 2010 of the ACM 1700 is generally rectangular in shape, preferablyconstructed of a strong, lightweight, rigid material that will protectthe internal components from mechanical and environmental exposure.Plastics may readily be used to construct the case 2010. The case 2010completely surrounds the internal components, being generally an 8-sidedbox. FIG. 19 shows the top 2012, right 2014, and rear 2016 surfaces ofthe ACM case 2010. Rear edges 2018 of the case joining the rear surface2016 with its adjoining surfaces may be beveled or rounded to facilitateinsertion of the ACM 1700 into the computer bay of the PCON. Notches2040 may be formed by projecting small surfaces inward from otherwisegenerally flat surfaces of the ACM case 2010. The notches 2040 may beused to engage with mechanical devices mounted in and about a computerbay. Such mechanical devices can be employed to secure the ACM intoposition within a computer bay for reliability and security. Openings2017 are formed into the rear surface 2016 of the ACM case 2010 throughwhich to project connectors 1930 a and 1930 b. In one embodiment thecase 2010 is approximately 5.75 inches wide by 6.5 inches deep by 1.6inches high.

Connectors 1930 a and 1930 b are part of the ACM-to-PCON Interconnectionas described earlier in reference to FIGS. 3 and 4. When the ACM 1700 isinserted into the computer bay of a peripheral console (PCON),connectors 1930 a and 1930 b mate with corresponding connectors locatedat the rear of the computer bay to electrically couple the ACM with thePCON containing the computer bay. Details concerning the ACM-to-PCONInterconnection can be found in the U.S. patent application entitled “ACommunication Channel and Interface Devices for Bridging ComputerInterface Buses,” already incorporated herein by reference. Theconnectors 1930 a and 1930 b used in one embodiment are connectorscomplying with the Device Bay industry standard as documented in “DeviceBay Interface Specification,” revision 0.85, Feb. 6, 1998. Suchconnectors have specifically been designed to stand up to the rigors ofrepeated insertion and withdrawal.

Cooling plate 2030 forms part of the top surface 2012 of ACM 1700. Thecooling plate 2030 may be mounted to, or project through an openingformed in, case 2010. Similarly, electromagnetic interference(EMI)/electrostatic discharge (ESD) grounding plate 2032 forms part ofthe right surface 2014 of ACM 1700. The grounding plate 2032 may bemounted to, or project through an opening formed in, case 2010. Coolingplate 2030 and grounding plate 2032 compressively mate with counterpartswhen the ACM is fully inserted into the computer bay. The counterpartslocated along the boundaries of the computer bay conduct dangerous heatand electrical charges away from the ACM. Inside the ACM, cooling plate2030 thermally couples to heat-sensitive components such as CPU 1710 bymethods well known in the art. Similarly, grounding plate 2032electrically couples to EMI/ESD-sensitive components, such as amicroprocessor, by methods well known in the art.

LCD display 2050 forms part of the right surface 2014 of ACM 1700. TheLCD display may be mounted to, or project through an opening formed in,case 2010. The LCD display may contain indicators about the status ofthe ACM. Such indicators may display, for example, the time-of-day froma time-of-day clock contained within the ACM, or the amount of chargeremaining in an ACM-resident battery, or certain configuration optionsrecorded in flash memory. The LCD display 2050 provides displaycapability for a limited amount of information, most useful when the ACMis separated from a PCON (and is thus separated from a full-capability,primary display device).

FIG. 19 b illustrates one possible embodiment of a computer bay. Acomputer bay 1890 acts as a receptacle for lodging an ACM (such as theone shown in FIG. 20) within a desktop PCON. The illustrated computerbay 1890 provides an ACM with housing and with signal flow, electricalgrounding, heat transfer, and mechanical connections. While manyphysical arrangements between the ACM and PCON are possible, the use ofan enclosed computer bay as the one illustrated in FIG. 20 b offers manyadvantages. For example, the illustrated computer bay 1890 providesphysical protection for the ACM. The computer bay may also be easilyincorporated into industry standard form factors used in the manufactureof desktop personal computers (e.g., the ACM and associated computer baycould be designed to fit within the volume occupied by a standard-sizedisk drive).

The computer bay 1890 appearing in FIG. 20 b is shown mounted within theconfines of PCON case 1802. The computer bay 1890 comprises frame 1891and signal flow, grounding, cooling, and locking components as describedbelow. Mounting flanges 1898 of frame 1891 may be used to attach thecomputer bay 1890 to the PCON structure. The computer bay 1890 isprominently defined by frame 1891 generally forming a cavity in which tolodge an ACM. As such, the interior cavity formed by frame 1891 closelyapproximates the exterior dimensions of a compatible ACM. The top 1893,right 1894, and rear 1895 sides of the computer bay frame 1891 arevisible. The computer bay frame 1891 also includes substantial bottomand left sides which are not shown. The front side of the frame 1891(not shown) is open to allow the insertion of the ACM. Frame 1891 isconstructed of metal for strength and to facilitate the conductance ofheat and undesired electrical currents away from the ACM.

In the presently described embodiment, the weight of an inserted ACM islargely borne by the bottom side (not shown) of computer bay frame 1891.Alternative embodiments are possible where, for example, the weight ofthe ACM is borne by rails running longitudinally down the right and leftsides of the computer bay cavity that engage corresponding groovesrunning longitudinally down the right and left sides of an ACM.

FIG. 20 illustrates the internal component layout for one embodiment ofan ACM. All components are contained within the confines of the ACM case510, except for connectors 1930 a and 1930 b which extend from the rearof the ACM 1700 to engage mating connectors (not shown) that will couplethe ACM circuitry with the PCON circuitry. Main circuit board 2110provides electrical connections for circuitry within the ACM andmounting for many of its components 1724, 1722, 17221, 1752, 1742, 1748,1920, and 1930. The fabrication and use of such circuit boards is wellknown and understood in the art. Connector 2122 is also mounted on maincircuit board 2110 and mates with mobile processor module 2120. Mobileprocessor module 2120 represents a form of packaging for amicroprocessor and related components. The illustrated mobile processormodule 2120 is a self-contained unit that includes a microprocessor1712, CPU cache 1714, and CPU bridge 1746 operatively interconnected bythe manufacturer. An example of one such module is the Pentium Processorwith MMX Technology Mobile Module from Intel Corporation (order number24 3515-001, September 1997). One skilled in the art recognizes thatdiscrete microprocessor, cache, and bridge could have been employed andmounted directly to the main circuit board.

The mobile processor module 2120 blocks the view, from the top, of thesystem BIOS 1724. Similarly, hard disk drive 1732 hides RAM memory 1722,the high performance graphics processor 1752, the host interfacecontroller 1920, and flash memory 1726. Memory upgrade socket 2130remains exposed to facilitate installation of additional RAM memory1722. Power regulator 1742, like the memory upgrade socket, enjoys agenerous amount of overhead clearance to accommodate its vertical size.The area including IDE controller 1748 also enjoys overhead clearance tofacilitate a cable connection with the hard disk drive 1732.

The functional interconnection and operation of components containedwithin the ACM and depicted in FIG. 20 has already been described inrelation to FIG. 18 for like numbered items appearing therein.

FIG. 21 is a block diagram of a peripheral console (PCON). A peripheralconsole couples with an ACM to form an operating personal computersystem. The peripheral console (PCON) supplies an ACM with primaryinput, display, and power supply; the ACM supplies the core computingpower and environment of the user. In the presently described embodimentthe physical PCON package 200 contains the PCON functional components1801 and the PCON side of the ACM-to-PCON Interconnection 1900. The PCONfunctional components 1801 comprise primary display 1810, a primaryinput 1820, a primary power supply 1830, interface and support 1840,secondary mass storage 1850, other devices 1860, and expansion slots1870.

The PCON side of the ACM-to-PCON Interconnection 1900 comprises aPeripheral Interface Controller (PIC) component 1940, a PCON connectorcomponent 1950, console-type component 1942, and flash memory device1948. The PIC 1940 and connector 1950 components couple the PCONfunctional components 1801 with the signals of an ACM-to-PCON interfacebus 1910 used to operatively connect an ACM with a PCON. The ACM-to-PCONinterface bus 1910 comprises conveyance for electrical power 1914 andsignals for a peripheral bus 1912, video 1916, video port 1917, andconsole-type 1918. The preferred ACM-to-PCON Interconnection 1900 isdescribed in detail in the U.S. patent application entitled “ACommunication Channel and Interface Devices for Bridging ComputerInterface Buses,” already incorporated herein by reference.

Connector component 1950 may be selected to mate directly with theconnector component 1930 of an ACM (shown in FIG. 18). Alternatively,connector component 1950 may be selected to mate with, for example, theconnector on one end of a cable intervening between the PCON and an ACMin a particular embodiment, such as cable 1964 shown in FIG. 19B. FIG.24 shows an attached computer module with a “Plug & Display” port anddirect power connection. The ACM-to-PCON interconnection described inthe aforementioned companion patent application has the advantage ofproviding reliable signal conveyance across low cost cables.

Flash memory device 1948 provides non-volatile storage. This storage maybe accessible to devices in both the ACM and the PCON, including thehost interface controller and the peripheral interface controller towhich it is connected. As such, flash memory 1948 may be used to storeconfiguration and security data to facilitate an intelligent matingbetween an ACM and a PCON that needs no participation of the CPU.

The primary display component 1810 of the PCON functional circuitry 1801of the presently described embodiment comprises integrated display panel1812 and video connector 1813. Integrated display panel 1812 is a colorLCD display panel having a resolution of 640 horizontal by 480 verticalpixels. 640-by-480 resolution is popularly considered to be the minimumscreen size to make practical use of the application software inwidespread use today. One skilled in the an recognizes that the type andresolution of the display can vary greatly from embodiment toembodiment, depending on factors such as cost and intended application.Any display device may be used, without departing from the scope andspirit of the invention, that provides principal visual output to thecomputer user for operating system and application software executing inits customary and intended fashion using the CPU component (1710 of FIG.17) of an ACM presently coupled to PCON 1800.

Integrated display panel 1812 is coupled to video signal bus 1849 anddisplays a screen image in response to video signals presented on bus1849. Certain pins of connector 1950 receive video output signals 1916of the ACM-to-PCON interface bus 1910 from a mated connector that iscoupled to an ACM. These certain pins of connector 1950 couple to videosignal bus 1849 which conveys the video output signals 316 throughoutthe PCON 1800 as needed. Video connector 1813 is exposed at the exteriorof PCON 1800 and couples to video signal bus 1849. Connector 1813permits easy attachment of an external display device that is compatiblewith the signals carried by bus 1849, such as a CRT monitor (not shown).The external display device may be used in addition, or as analternative, to integrated display panel 1812.

The isolation of the relatively heavy and sizable primary display 1810from the core computing power and user environment contained within anACM represents a further advantage of the present invention.

The primary input component 1820 of the PCON functional circuitry 1801of the presently described embodiment comprises keyboard interfacecircuitry 1822, keyboard connector 1823, pointer interface circuitry1824, and pointer connector 1825. Keyboard interface circuitry 1822 andpointer interface circuitry 1824 connect to ISA bus 1845 and are therebycoupled to the CPU component (1710 of FIG. 17) of any ACM attached toPCON 1800. Keyboard interface circuitry 1822 interfaces a standardcomputer keyboard (not shown), attached at connector 1823, to ISA bus1845. Pointer interface circuitry 1822 interfaces a standard computerpointing device (not shown), such as a computer mouse attached atconnector 1825, to ISA bus 1845. Computer keyboards, pointing devices,connectors 1823. 1825. keyboard interface circuitry 1822, and pointerinterface circuitry 1824 are well known in the art. The isolation of therelatively heavy and sizable primary input devices 1820 from the corecomputing power and user environment contained within an ACM representsa further advantage of the present invention.

The primary power supply component 1830 of the PCON functional circuitry1801 of the presently described embodiment provides electrical energyfor the sustained, normal operation of the PCON 1800 and any ACM coupledto connector 1950. The power supply may be of the switching variety wellknown in the art that receives electrical energy from an AC source 1889,such as a wall outlet. Power supply 1830 reduces the alternating currentinput voltage, to a number of distinct outputs of differing voltages andcurrent capacities. The outputs of power supply 1830 are applied topower bus 1831. Power bus 1831 distributes the power supply outputs tothe other circuitry within the PCON 1800. Bus 1831 also connects tocertain pins of connector 1950 to provide the electrical power 1914 foran ACM conveyed by ACM-to-PCON interconnection 1900. The isolation ofthe usually heavy power supply 1830 from the core computing power anduser environment contained within the ACM represents a further advantageof the present invention.

The interface and support component 1840 of the PCON functionalcircuitry 1801 of the presently described embodiment comprisesperipheral bridge 1846, diskette controller 1842, IDE controller 1848,and signal conveyance paths 1841, 1843, 1844, 1845, 1847 and 1849.Peripheral bridge 1846 couples PCI peripheral bus 1841 with peripheralbusses of other formats such as ISA peripheral bus 1845 and others 1847.PCI and ISA peripheral busses are industry standards, well known andunderstood in the art. Other peripheral busses 1847 may include, forexample, a bus compliant with the universal serial bus (USB) industrystandard. While other embodiments of a peripheral console 1800 mayinclude a single peripheral bus that is coupled to an attached ACM viaACM-to-PCON interconnection 1900, such as PCI bus 1841, this embodimentincludes peripheral bridge 1846 to establish additional busses 1845,1847. The additional busses 1845, 1847 permit the use of the manylow-cost and readily available components compatible with these busspecifications.

Diskette controller 1842 interfaces a floppy disk drive 1854 with theCPU component 1710 of an attached ACM (shown in FIG. 18) so that the CPUmay control and use the diskette drive 1854 hardware to store andretrieve data. Diskette controller 1842 couples to the CPU via aconnection to ISA bus 1845. Diskette controller 1842 connects to thediskette drive 1854 via one of device cables 1843.

Similarly, IDE controller 1848 interfaces a hard disk drive 1852 and aCDROM drive 1856 with the CPU component 1710 of an attached ACM (shownin FIG. 18) so that the CPU may control and use the hard disk drive 1852and CDROM 1856 hardware to store and retrieve data. IDE controller 1848couples to the CPU via connection to PCI peripheral bus 1841. IDEcontroller 1848 connects to each of hard disk drive 1852 and CD-ROMdrive 1856 via one of device cables 1843. Some embodiments of PCON 1800may take advantage of VLSI integrated circuits such as an 82371 SB(PIIX4) integrated circuit from Intel Corporation. An 82371SB integratedcircuit includes circuitry for both the peripheral bridge 1846 and theIDE controller 1848 in a single package.

The secondary mass storage component 1850 of the PCON functionalcircuitry 1801 of the presently described embodiment comprises diskettedrive 1854, hard disk drive 1852, and CD-ROM drive 1856. Secondary massstorage 1850 generally provides low-cost, non-volatile storage for datafiles which may include software program files. Data files stored onsecondary mass storage 1850 are not part of a computer user's corecomputing power and environment. Secondary mass storage 1850 may be usedto store, for example, seldom used software programs, software programsthat are used only with companion hardware devices installed in the sameperipheral console 1800, or archival copies of data files that aremaintained in primary mass storage 1750 of an ACM (shown in FIG. 18).Storage capacities for secondary mass storage 1850 devices may vary fromthe 1.44 megabytes of the 3.5-inch high density diskette drive 1854, tomore than 10 gigabytes for a large format (5-inch) hard disk drive 1852.Hard disk drive 1852 employs fixed recording media, while diskette drive1854 and CD-ROM drive 1856 employ removable media. Diskette drive 1854and hard disk drive 1852 support both read and write operations (i.e.,data stored on their recording media may be both recalled and modified)while CD-ROM drive 1856 supports only read operations.

The other devices component 1860 of the PCON functional circuitry 1801of the presently described embodiment comprises a video capture card. Avideo capture card accepts analog television signals, such as thosecomplying with the NTSC standard used for television broadcast in theUnited States, and digitizes picture frames represented by the analogsignal for processing by the computer. Video capture cards at presentare considered a specialty, i.e., not ubiquitous, component of personalcomputer systems. Digitized picture information from video capture card1860 is carried via signal conveyance path 1844 to the peripheralinterface controller 1940 which transforms it to the video port signals1917 of the ACM-to-PCON interconnection 1900 for coupling to theadvanced graphics processor 1752 in an attached ACM (shown in FIG. 18).

Video capture card 1860 is merely representative of the many types of“other” devices that may be installed in a PCON to expand thecapabilities of the personal computer. Sound cards and laboratory dataacquisition cards are other examples. Video capture card 1860 is showninstalled in one of expansion slots 1870 for coupling to the interfaceand control circuitry 1840 of the PCON. Any of other devices 1860 couldbe coupled to the interface and control circuitry 1840 of the PCON bydifferent means, such as direct installation on the circuit board thatincludes the interface and control circuitry 1840; e.g., a motherboard.

The expansion slots component 1870 of the PCON functional circuitry 1801of the presently described embodiment comprises PCI connectors 1871 andISA connectors 1872. A circuit card may be inserted into one of theconnectors 1871, 1872 in order to be operatively coupled with the CPU1710 of an attached ACM (shown in FIG. 18). Each of connectors 1871electrically connects to PCI bus 1841, and may receive and hold aprinted circuit card which it electrically couples to PCI bus 1841. Eachof connectors 1872 electrically connects to ISA bus 1845, and mayreceive and hold a printed circuit card which it electrically couples toISA bus 1845. The PCI 1841 and ISA 1845 busses couple to the CPU 1710 ofan attached ACM (shown in FIG. 18) by circuitry already described.

An embodiment of a detachable computing module in accordance with thepresent invention, for attachment to a peripheral console for forming afully operational computer system, comprises, an enclosure, a CPU, amemory coupled to said CPU, and a mass storage coupled to said CPU. Themodule further comprises interconnection circuitry coupled to said CPU,said interconnection circuitry connectable to a peripheral console. TheCPU is uncoupled from any primary input circuitry when saidinterconnection circuitry is disconnected from a peripheral console.

An alternative embodiment of a detachable computing module in accordancewith the present invention, for attachment to a peripheral console forforming a fully operational computer system, comprises an enclosure, aCPU, a memory coupled to said CPU, and a mass storage coupled to saidCPU. The module further comprises interconnection circuitry coupled tosaid CPU, said interconnection circuitry connectable to a peripheralconsole. The CPU is uncoupled from any primary output circuitry whensaid interconnection circuitry is disconnected from a peripheralconsole.

Various modifications to the preferred embodiment can be made withoutdeparting from the spirit and scope of the invention. (A limited numberof modifications have already been described in the precedingdiscussion.) For example, a particular embodiment may insert anotherlayer of bus bridging between the CPU bridge and the Peripheral bridge.This may be desirable if, for example, a vendor wants to implement aproprietary, general-purpose bus having intermediate performancecharacteristics that fall between those of the high-performance generalpurpose bus originating at the CPU, and the slower general purpose PCIbus. Thus, the foregoing description is not intended to limit theinvention as set forth.

In most embodiments, the ACM includes an enclosure such as the onedescribed with the following components, which should not be limiting:

1) A CPU with cache memory;

2) Core logic device or means;

3) Main memory;

4) A single primary Hard Disk Drive (“HDD”) that has a security program;

5) Flash memory with system BIOS and programmable user password;

6) Operating System, application software, data files on primary HDD;

7) An interface device and connectors to peripheral console;

8) A software controllable mechanical lock, lock control means, andother accessories.

The ACM connects to a peripheral console with power supply, a displaydevice, an input device, and other elements. Some details of theseelements with the present security system are described in more detailbelow.

FIG. 22 is a simplified layout diagram of a security system for acomputer system according to an embodiment of the present invention.This diagram is merely an illustration and should not limit the scope ofthe claims herein. One of ordinary skill in the an would recognize othervariations, modifications. and alternatives. The layout diagramillustrates the top-view of the module 22, where the backside components(e.g., Host Interface Controller) are depicted in dashed lines. Thelayout diagram has a first portion, which includes a central processingunit (“CPU”) module 2200, and a second portion, which includes a harddrive module 2220. A common printed circuit board 2237 houses thesemodules and the like. Among other features, the ACM includes the centralprocessing unit module 2200 with a cache memory 2205, which is coupledto a north bridge unit 2221, and a host interface controller 2201. Thehost interface controller includes a lock control 2203. As shown, theCPU module is disposed on a first portion of the attached computermodule, and couples to connectors 2217. Here, the CPU module isspatially located near connector 2217.

The CPU module can use a suitable microprocessing unit, microcontroller,digital signal processor, and the like. In a specific embodiment, theCPU module uses, for example, a 400 MHz Pentium II microprocessor modulefrom Intel Corporation and like microprocessors from AMD Corporation,Cyrix Corporation (now National Semiconductor Corporation), and others.In other aspects, the microprocessor can be one such as the CompaqComputer Corporation Alpha Chip, Apple Computer Corporation PowerPC G3processor, and the like. Further, higher speed processors arecontemplated in other embodiments as technology increases in the future.

In the CPU module, host interface controller 2201 is coupled toBIOS/flash memory 2205. Additionally, the host interface controller iscoupled to a clock control logic, a configuration signal, and aperipheral bus. The present invention has a host interface controllerthat has lock control 2203 to provide security features to the presentACM. Furthermore, the present invention uses a flash memory thatincludes codes to provide password protection or other electronicsecurity methods.

The second portion of the attached computer module has the hard drivemodule 2220. Among other elements, the hard drive module includes northbridge 2221, graphics accelerator 2223, graphics memory 2225, a powercontroller 2227, an IDE controller 2229, and other components. Adjacentto and in parallel alignment with the hard drive module is a personalcomputer interface (“PCI”) bus 2231, 2232. A power regulator 435 isdisposed near the PCI bus.

In a specific embodiment, north bridge unit 2221 often couples to acomputer memory, to the graphics accelerator 2223, to the IDEcontroller, and to the host interface controller via the PCI bus.Graphics accelerator 2223 typically couples to a graphics memory 2223,and other elements. IDE controller 2229 generally supports and providestiming signals necessary for the IDE bus. In the present embodiment, theIDE controller is embodied as a 643U2 PCI- to IDE chip from CMDTechnology, for example. Other types of buses than IDE are contemplated,for example EIDE, SCSI, 1394, and the like in alternative embodiments ofthe present invention.

The hard drive module or mass storage unit 2220 typically includes acomputer operating system, application software program files, datafiles, and the like. In a specific embodiment, the computer operatingsystem may be the Windows98 operating system from Microsoft Corporationof Redmond Wash. Other operating systems, such as WindowsNT, MacOS8,Unix, and the like are also contemplated in alternative embodiments ofthe present invention. Further, some typical application softwareprograms can include Office98 by Microsoft Corporation, Corel PerfectSuite by Corel, and others. Hard disk module 2220 includes a hard diskdrive. The hard disk drive, however, can also be replaced by removablehard disk drives, read/write CD ROMs, flash memory, floppy disk drives,and the like. A small form factor, for example 2.5″, is currentlycontemplated, however, other form factors, such as PC card, and the likeare also contemplated. Mass storage unit 2240 may also support otherinterfaces than IDE. Among other features, the computer system includesan ACM with security protection. The ACM connects to the console, whichhas at least the following elements, which should not be limiting.

1) Connection to input devices, e.g. keyboard or mouse;

2) Connection to display devices, e.g. Monitor;

3) Add-on means, e.g. PCI add-on slots;

4) Removable storage media subsystem, e.g. Floppy drive, CDROM drive;

5) Communication device, e.g. LAN or modem;

6) An interface device and connectors to ACM;

7) A computer module bay with a notch in the frame for ACM's lock; and

8) Power supply and other accessories.

As noted, the computer module bay is an opening in a peripheral consolethat receives the ACM. The computer module bay provides mechanicalsupport and protection to ACM. The module bay also includes, among otherelements, a variety of thermal components for heat dissipation, a framethat provides connector alignment, and a lock engagement, which securesthe ACM to the console. The bay also has a printed circuit board tomount and mate the connector from the ACM to the console. The connectorprovides an interface between the ACM and other accessories.

FIG. 23 is a simplified block diagram 2300 of a security system for acomputer module according to an embodiment of the present invention.This diagram is merely an illustration and should not limit the scope ofthe claims herein. One of ordinary skill in the art would recognizeother variations, modifications, and alternatives. The block diagram2300 has a variety of features such as those noted above, as well asothers. In the present diagram, different reference numerals are used toshow the operation of the present system.

The block diagram is an attached computer module 2300. The module 2300has a central processing unit, which communicates to a north bridge2341, by way of a CPU bus 2327. The north bridge couples to main memory2323 via memory bus 2329. The main memory can be any suitable high speedmemory device or devices such as dynamic random access memory (“DRAM”)integrated circuits and others. The DRAM includes at least 32 Meg. or 64Meg. and greater of memory, but can also be less depending upon theapplication. Alternatively, the main memory can be coupled directly withthe CPU in some embodiments. The north bridge also couples to a graphicssubsystem 2315 via bus 2342. The graphics subsystem can include agraphics accelerator, graphics memory, and other devices. Graphicssubsystem transmits a video signal to an interface connector, whichcouples to a display, for example.

The attached computer module also includes a primary hard disk drivethat serves as a main memory unit for programs and the like. The harddisk can be any suitable drive that has at least 2 GB and greater. Asmerely an example, the hard disk is a Marathon 2250 (2.25 GB, 2½ inchdrive) product made by Seagate Corporation of Scotts Valley, but can beothers. The hard disk communicates to the north bridge by way of a harddisk drive controller and bus lines 2302 and 2331. The hard disk drivecontroller couples to the north bridge by way of the host PCI bus, whichconnects bus 2337 to the north bridge. The hard disk includes computercodes that implement a security program according to the presentinvention. Details of the security program are provided below.

The attached computer module also has a flash memory device 2305 with aBIOS. The flash memory device 2305 also has codes for a user passwordthat can be stored in the device. The flash memory device generallypermits the storage of such password without a substantial use of power,even when disconnected. As merely an example, the flash memory devicehas at least 4 Meg. or greater of memory, or 16 Meg. or greater ofmemory. A host interface controller 2307 communications to the northbridge via bus 2335 and host PCI bus. The host interface controller alsohas a Lock control 2309, which couples to a lock. The lock is attachedto the module and has a manual override to the lock on the hostinterface controller in some embodiments. Host interface controller 2307communicates to the console using bus 2311, which couples to connection2313.

FIGS. 25 and 26 are tables including the pin number, symbol, signalstandard and description for the pins on the peripheral and videoconnectors, respectively.

In a preferred embodiment, the present invention uses a passwordprotection scheme to electronically prevent unauthorized access to thecomputer module. The present password protection scheme uses acombination of software, which is a portion of the security program, anda user password, which can be stored in the flash memory device 505. Byway of the flash memory device, the password does not become erased byway of power failure or the lock. The password is substantially fixed incode, which cannot be easily erased. Should the user desire to changethe password, it can readily be changed by erasing the code, which isstored in flash memory and a new code (i.e., password) is written intothe flash memory. An example of a flash memory device can include aIntel Flash 28F800F3 series flash, which is available in 8 Mbit and 16Mbit designs. Other types of flash devices can also be used, however.Details of a password protection method are further explained below byway of the FIGS.

In a specific embodiment, the present invention also includes areal-time clock 510 in the ACM, but is not limited. The real-time clockcan be implemented using a reference oscillator 14.31818 MHz 508 thatcouples to a real-time clock circuit. The real-time clock circuit can bein the host interface controller. An energy source 506 such as a batterycan be used to keep the real-time clock circuit running even when theACM has been removed from the console. The real-time clock can be usedby a security program to perform a variety of functions. As merely anexample, these functions include: (1) fixed time period in which the ACMcan be used, e.g., ACM cannot be used at night; (2) programmed ACM to beused after certain date, e.g., high security procedure during owner'svacation or non use period; (3) other uses similar to a programmabletime lock. Further details of the present real-time clock are describedin the application listed under Ser. No. 09/183,816 noted above.

In still a further embodiment, the present invention also includes apermanent password or user identification code to identify the computermodule. In one embodiment, the permanent password or user code is storedin a flash memory device. Alternatively, the permanent password or usercode is stored in the central processing unit. The password or user codecan be placed in the device upon manufacture of such device.Alternatively, the password or user code can be placed in the device bya one time programming techniques using, for example, fuses or the like.The present password or user code provides a permanent “finger print” onthe device, which is generally hardware. The permanent finger print canbe used for identification purposes for allowing the user of thehardware to access the hardware itself, as well as other systems. Theseother systems include local and wide area networks. Alternatively, thesystems can also include one or more servers. The present password anduser identification can be quite important for electronic commerceapplications and the like. In one or more embodiments, the permanentpassword or user code can be combined with the password on flash memoryfor the security program, which is described below in more detail.

In one aspect of the invention, the user password is programmable. Thepassword can be programmable by way of the security program. Thepassword can be stored in a flash memory device within the ACM.Accordingly, the user of the ACM and the console would need to have theuser password in order to access the ACM. In the present aspect, thecombination of a security program and user password can provide the usera wide variety of security functions as follows:

1) Auto-lock capability when ACM is inserted into CMB;

2) Access privilege of program and data;

3) Password matching for ACM removal; and

4) Automatic HDD lock out if tempering is detected.

In still a further embodiment, the present invention also includes amethod for reading a permanent password or user identification code toidentify the computer module.

In one embodiment, the permanent password or user code is stored in aflash memory device. Alternatively, the permanent password or user codeis stored in the central processing unit. The password or user code canbe placed in the device upon manufacture of such device. Alternatively,the password or user code can be placed in the device by a one timeprogramming techniques using, for example, fuses or the like. Thepresent password or user code provides a permanent “finger print” on thedevice, which is generally hardware. The permanent finger print can beused for identification purposes for allowing the user of the hardwareto access the hardware itself, as well as other systems. These othersystems include local and wide area networks. Alternatively, the systemscan also include one or more servers. The present method allows a thirdparty confirm the user by way of the permanent password or user code.The present password and user identification can be quite important forelectronic commerce applications and the like, which verify the usercode or password. In one or more embodiments, the permanent password oruser code can be combined with the password on flash memory for thesecurity program.

The above embodiments are described generally in terms of hardware andsoftware. It will be recognized, however, that the functionality of thehardware can be further combined or even separated. The functionality ofthe software can also be further combined or even separated. Hardwarecan be replaced, at times, with software. Software can be replaced, attimes, with hardware. Accordingly, the present embodiments should not beconstrued as limiting the scope of the claims here. One of ordinaryskill in the art would recognize other variations, modifications, andalternatives.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. Therefore, the above description and illustrations should not betaken as limiting the scope of the present invention which is defined bythe appended claims.

While the present invention has been particularly described with respectto the illustrated embodiments, it will be appreciated that variousalterations, modifications and adaptations may be made based on thepresent disclosure, and are intended to be within the scope of thepresent invention. While the invention has been described in connectionwith what are presently considered to be the most practical andpreferred embodiments, it is to be understood that the present inventionis not limited to the disclosed embodiments but, on the contrary, isintended to cover various modifications and equivalent arrangementsincluded within the scope of the appended claims.

What is claimed is:
 1. A computer, comprising: an integrated centralprocessing unit, interface controller and Phase-Locked Loop (PLL) clockcircuitry in a single chip, a Low Voltage Differential Signal (LVDS)channel directly extending from the interface controller to conveyaddress and data bits of a Peripheral Component Interconnect (PCI) bustransaction in a serial form, wherein the first LVDS channel comprises afirst unidirectional, differential signal pair to convey data in a firstdirection and a second unidirectional, differential signal pair toconvey data in a second, opposite direction; and wherein the PLL clockcircuitry generates different clock frequencies, and the interfacecontroller conveys the PCI bus transaction through the LVDS channelbased on the different clock frequencies.
 2. The computer of claim 1wherein the interface controller conveys the PCI bus transaction throughthe LVDS channel based on a selected frequency of the different clockfrequencies.
 3. The computer of claim 1 wherein the interface controlleris configurable to convey the PCI bus transaction with differentserialized forms through the LVDS channel on different numbers ofdifferential signal pairs.
 4. A computer, comprising: a centralprocessing unit; an integrated peripheral bridge, interface controller,and Phase-Locked Loop (PLL) clock circuitry in a single chip, directlycoupled to the central processing unit without any intervening PCI bus;a low voltage differential signal (LVDS) channel directly extending fromthe interface controller comprising at least two serial channels ofunidirectional, differential signal pairs to convey data in oppositedirections, wherein the LVDS channel conveys encoded address and databits of a Peripheral Component Interconnect (PCI) bus transaction inserial form; and wherein the PLL clock circuitry generates differentclock frequencies, and the interface controller conveys the PCI bustransaction through the LVDS channel based on the different clockfrequencies.
 5. The computer of claim 4 wherein the interface controllerconveys the PCI bus transaction with different data rate frequenciesthrough the LVDS channel based on the different clock frequencies. 6.The computer of claim 4 wherein the interface controller is configurableto convey the PCI bus transaction with different serialized formsthrough the LVDS channel on different numbers of differential signalpairs.
 7. A printed circuit board, comprising: a central processing unitconnected directly to a first Low Voltage Differential Signal (LVDS)channel to convey encoded address and data bits of a PeripheralComponent Interconnect (PCI) bus transaction in serial form, wherein theLVDS channel comprises four or more unidirectional, differential signalline pairs to convey data in a first direction, and four or moreunidirectional, differential signal line pairs to convey data in asecond, opposite direction, an interface controller comprisingPhased-Locked Loop (PLL) clock circuitry, coupled to a second LowVoltage Differential Signal (LVDS) channel with two sets ofunidirectional, differential signal line pairs to convey serial data inopposite direction, and a socket for a system memory module directlycoupled to the central processing unit.
 8. The printed circuit board ofclaim 7, wherein the interface controller is configurable to conveyencoded address and data bits of a Peripheral Component Interconnect(PCI) bus transaction with different serialized forms, through thesecond LVDS channel on different numbers of differential signal pairs.9. The printed circuit board of claim 7, wherein the PLL clock circuitrygenerates different clock frequencies; and wherein the interfacecontroller generates a data transfer frequency based on one of thedifferent clock frequencies, to convey encoded address and data bits ofa Peripheral Component Interconnect (PCI) bus transaction through thesecond LVDS channel.
 10. A printed circuit board, comprising: a centralprocessing unit; a peripheral bridge directly coupled to the centralprocessing unit without any intervening Peripheral ComponentInterconnect (PCI) bus; a low voltage differential signal (LVDS) channeldirectly extending from the peripheral bridge comprising twounidirectional, serial channels of multiple differential signal linepairs to convey data in opposite directions, wherein the LVDS channelconveys address and data bits of a PCI bus transaction in serial form;and a network controller coupled to the central processing unit.
 11. Theprinted circuit board of claim 10 wherein the peripheral bridgecomprises an interface controller directly coupled to the LVDS channel,wherein the interface controller is configurable to convey the PCI bustransaction through the LVDS channel with different serialized forms ondifferent numbers of differential signal pairs.
 12. The printed circuitboard of claim 11 wherein the interface controller couples toPhased-Locked Loop (PLL) clock circuitry, and wherein the interfacecontroller generates different data transfer frequencies based ondifferent frequencies generated by the PLL clock circuitry, to conveythe PCI bus transaction through the LVDS channel.
 13. A computer,comprising: an integrated central processing unit and interfacecontroller in a single chip; a first Low Voltage Differential Signal(LVDS) channel directly extending from the interface controller toconvey address and data bits of a Peripheral Component Interconnect(PCI) bus transaction in a serial bit stream, wherein the first LVDSchannel comprises first unidirectional, multiple, differential signalpairs to convey data in a first direction and second unidirectional,multiple, differential signal pairs to convey data in a second, oppositedirection; and a system memory directly coupled to the integratedcentral processing unit and interface controller.
 14. The computer ofclaim 13, wherein the interface controller is configurable to convey thePCI bus transaction through the LVDS channel on different numbers ofdifferential signal pairs.
 15. The computer of claim 13, furthercomprising a connector adapted to convey a serial bit stream of addressand data bits of a PCI bus transaction through a second Low VoltageDifferential Signal (LVDS) channel comprising two unidirectional,differential signal pairs that transmit data in opposite directions. 16.The computer of claim 15, wherein the second LVDS channel isconfigurable in different numbers of differential signal pairs totransmit the PCI bus transaction.
 17. The computer of claim 13, whereinthe interface controller couples to Phase-Locked Loop (PLL) clockcircuitry, and wherein the interface controller generates a datatransfer signal to convey the PCI bus transaction through the LVDSchannel based on one of the different clock frequencies generated by thePLL clock circuitry.
 18. A computer system, comprising: a computer witha connector configurable for coupling to a console; an integratedcentral processing unit, graphics subsystem and interface controller ina single chip; a first Low Voltage Differential Signal (LVDS) channeldirectly coupled to the interface controller, adapted to convey encodedaddress and data bits of a Peripheral Component Interconnect (PCI) bustransaction in serial form, wherein the first LVDS channel comprises afirst plurality of unidirectional, differential signal pairs to conveydata in a first direction and a second plurality of unidirectional,differential signal pairs to convey data in a second, oppositedirection; wherein the integrated graphics subsystem directly outputsdigital video display signals in a third differential signal channel;and wherein the integrated interface controller is configurable toconvey the PCI bus transaction on different numbers of differentialsignal pairs.
 19. The computer system of claim 18, wherein the interfacecontroller couples to Phased-Locked Loop (PLL) clock circuitry, andwherein the interface controller generates a first data transfer signalto convey the PCI bus transaction through the LVDS channel based on oneof the different clock frequencies generated by the PLL clock circuitry.20. The computer system of claim 19, wherein the interface controllergenerates a second data transfer signal to convey the PCI bustransaction through the LVDS channel based on another one of thedifferent clock frequencies generated by the PLL clock circuitry. 21.The computer system of claim 18, wherein the interface controller isconfigurable to convey the PCI bus transaction through the first LVDSchannel on different numbers of differential signal pairs.
 22. Acomputer, comprising: an integrated central processing unit, graphicssubsystem and interface controller in a single chip, wherein theintegrated interface controller is directly coupled to a first LowVoltage Differential Signal (LVDS) channel comprising two sets ofunidirectional, multiple serial bit channels communicating encodedaddress and data bits of a Peripheral Component Interconnect (PCI) bustransaction in opposite directions; a connector adapted to conveydigital video display signals from a differential signal channeldirectly connected to the integrated graphics subsystem, and a serialbit stream of encoded address and data bits of a PCI bus transaction ina second LVDS channel comprising unidirectional, differential signalpairs; and wherein the computer couples to a console through theconnector.
 23. The computer of claim 22, wherein the interfacecontroller is configurable to couple to different numbers of serial bitchannels to convey the PCI bus transaction through the LVDS channel. 24.The computer system of claim 22, wherein the second LVDS channel isconfigurable in different numbers of differential signal pairs totransmit the PCI bus transaction.
 25. The computer of claim 22, whereinthe integrated interface controller couples to Phase-Locked Loop (PLL)clock circuitry in the single chip, and wherein the interface controllergenerates different data transfer frequencies to convey the PCI bustransaction through the LVDS channel based on different clockfrequencies generated by the PLL clock circuitry.
 26. The computer ofclaim 22, wherein the differential signal channel uses TransitionMinimized Differential Signaling (TMDS) to convey digital video displaysignals.
 27. A computer comprising an integrated central processing unitand graphics subsystem in a single chip directly coupled to a first LowVoltage Differential Signal (LVDS) channel comprising two sets ofunidirectional, multiple serial bit channels transmitting encodedaddress and data bits of a Peripheral Component Interconnect (PCI) bustransaction in opposite directions; an interface controller directlycoupled to a second LVDS channel comprising two sets of unidirectional,serial bit channels to transmit data in opposite directions; a connectorcoupled to the interface controller adapted to convey a serial bitstream of encoded address and data bits of a PCI bus transaction fromthe second LVDS channel; and a console, wherein the computer is adaptedto couple to the console through the connector.
 28. The computer ofclaim 27, wherein the interface controller is configurable to couple todifferent numbers of serial bit channels to convey the PCI bustransaction to the connector through the second LVDS channel.
 29. Thecomputer of claim 27, wherein the first LVDS channel is adaptable todifferent data transfer frequencies to convey the PCI bus transaction.30. A modular system, comprising: a computer comprising: a centralprocessing unit directly connected to a first Low Voltage DifferentialSignal (LVDS) channel comprising two sets of four or more,unidirectional, differential signal pairs transmitting data packetsserially in opposite directions, wherein the data packets communicateencoded address and data bits of a Peripheral Component Interconnect(PCI) bus transaction in serial form, a system memory directly connectedto the central processing unit, and a connector adapted to conveydigital video display signals and to transmit a serial bit stream ofencoded address and data bits of a PCI bus transaction through a secondLVDS channel comprising two sets of unidirectional, differential signalpairs in opposite direction; and a console, wherein the computer isadapted to couple to the console through the connector.
 31. The modularcomputer of claim 30, wherein the first LVDS channel is adaptable todifferent data transfer frequencies to convey the PCI bus transaction.32. The modular computer of claim 30, wherein the second LVDS channel isconfigurable in different numbers of differential signal pairs to conveythe PCI bus transaction.
 33. A computer, comprising: a centralprocessing unit comprising an interface controller directly connected toa first Low Voltage Differential Signal (LVDS) channel comprising atleast two sets of unidirectional, multiple, differential signal pairstransmitting encoded address and data bits of a Peripheral ComponentInterconnect (PCI) bus transaction in opposite directions, wherein theinterface controller is configured to convey the PCI bus transactionthrough the LVDS channel in different numbers of differential signalpairs; a system memory directly connected to the central processingunit; a mass storage device coupled to the central processing unit; anda second Low Voltage Differential Signal (LVDS) channel comprising twosets of unidirectional, differential signal pairs transmitting dataserially in opposite directions, wherein the second LVDS channel is apoint-to-point data communication link.
 34. The computer of claim 33,wherein the computer couples to a console and wherein the centralprocessing unit communicates to the console through the second LVDSchannel utilizing a Universal Serial Bus (USB) protocol.
 35. Thecomputer of claim 33, wherein the interface controller comprisesPhased-Locked Loop (PLL) clock circuitry, and wherein the interfacecontroller generates a data transfer signal to convey the PCI bustransaction through the first LVDS channel based on one of the differentclock frequencies generated by the PLL clock circuitry.
 36. A computer,comprising: an integrated central processing unit and graphics subsystemin a single chip; a first Low Voltage Differential Signal (LVDS) channeldirectly extending from the integrated central processing unit andgraphics subsystem, wherein the first LVDS channel comprises a firstunidirectional, differential signal pair to convey data in a firstdirection and a second unidirectional, differential signal pair toconvey data in a second, opposite direction, wherein the first LVDSchannel conveys data using a Universal Serial Bus (USB) protocol; asystem memory directly coupled to the integrated central processing unitand graphics subsystem; and a graphics memory directly coupled to theintegrated central processing unit and graphics subsystem.
 37. Thecomputer of claim 36, further comprising a connector adapted to conveyencoded address and data bits of a Peripheral Component Interconnect(PCI) bus transaction through a second LVDS channel comprising twounidirectional, differential signal pairs that transmit data in oppositedirections.
 38. The computer of claim 37, wherein the second LVDSchannel is configurable to convey the PCI bus transaction on differentnumbers of differential signal pairs.
 39. A computer, comprising: anintegrated central processing unit and interface controller in a singlechip; a Low Voltage Differential Signal (LVDS) channel directlyextending from the integrated central processing unit and interfacecontroller to convey encoded address and data bits of a PeripheralComponent Interconnect (PCI) bus transaction in a serial form, whereinthe LVDS channel comprises a first unidirectional, multiple,differential signal line pairs to convey data in a first direction and asecond unidirectional, multiple, differential signal line pairs toconvey data in a second, opposite direction; a socket for a systemmemory module, directly coupled to the integrated central processingunit and interface controller; and wherein the interface controller isconfigurable to convey the PCI bus transaction through the LVDS channelon different numbers of differential signal line pairs.
 40. The computerof claim 39, further comprising a second Low Voltage Differential Signal(LVDS) channel comprising two sets of unidirectional, differentialsignal pairs transmitting data serially in opposite directions to conveydata using a Universal Serial Bus (USB) protocol.